yuzu/src/core/hle/service/sockets/bsd.h

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// SPDX-FileCopyrightText: Copyright 2018 yuzu Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later
#pragma once
#include <memory>
#include <span>
#include <vector>
#include "common/common_types.h"
Implement SSL service This implements some missing network APIs including a large chunk of the SSL service, enough for Mario Maker (with an appropriate mod applied) to connect to the fan server [Open Course World](https://opencourse.world/). Connecting to first-party servers is out of scope of this PR and is a minefield I'd rather not step into. ## TLS TLS is implemented with multiple backends depending on the system's 'native' TLS library. Currently there are two backends: Schannel for Windows, and OpenSSL for Linux. (In reality Linux is a bit of a free-for-all where there's no one 'native' library, but OpenSSL is the closest it gets.) On macOS the 'native' library is SecureTransport but that isn't implemented in this PR. (Instead, all non-Windows OSes will use OpenSSL unless disabled with `-DENABLE_OPENSSL=OFF`.) Why have multiple backends instead of just using a single library, especially given that Yuzu already embeds mbedtls for cryptographic algorithms? Well, I tried implementing this on mbedtls first, but the problem is TLS policies - mainly trusted certificate policies, and to a lesser extent trusted algorithms, SSL versions, etc. ...In practice, the chance that someone is going to conduct a man-in-the-middle attack on a third-party game server is pretty low, but I'm a security nerd so I like to do the right security things. My base assumption is that we want to use the host system's TLS policies. An alternative would be to more closely emulate the Switch's TLS implementation (which is based on NSS). But for one thing, I don't feel like reverse engineering it. And I'd argue that for third-party servers such as Open Course World, it's theoretically preferable to use the system's policies rather than the Switch's, for two reasons 1. Someday the Switch will stop being updated, and the trusted cert list, algorithms, etc. will start to go stale, but users will still want to connect to third-party servers, and there's no reason they shouldn't have up-to-date security when doing so. At that point, homebrew users on actual hardware may patch the TLS implementation, but for emulators it's simpler to just use the host's stack. 2. Also, it's good to respect any custom certificate policies the user may have added systemwide. For example, they may have added custom trusted CAs in order to use TLS debugging tools or pass through corporate MitM middleboxes. Or they may have removed some CAs that are normally trusted out of paranoia. Note that this policy wouldn't work as-is for connecting to first-party servers, because some of them serve certificates based on Nintendo's own CA rather than a publicly trusted one. However, this could probably be solved easily by using appropriate APIs to adding Nintendo's CA as an alternate trusted cert for Yuzu's connections. That is not implemented in this PR because, again, first-party servers are out of scope. (If anything I'd rather have an option to _block_ connections to Nintendo servers, but that's not implemented here.) To use the host's TLS policies, there are three theoretical options: a) Import the host's trusted certificate list into a cross-platform TLS library (presumably mbedtls). b) Use the native TLS library to verify certificates but use a cross-platform TLS library for everything else. c) Use the native TLS library for everything. Two problems with option a). First, importing the trusted certificate list at minimum requires a bunch of platform-specific code, which mbedtls does not have built in. Interestingly, OpenSSL recently gained the ability to import the Windows certificate trust store... but that leads to the second problem, which is that a list of trusted certificates is [not expressive enough](https://bugs.archlinux.org/task/41909) to express a modern certificate trust policy. For example, Windows has the concept of [explicitly distrusted certificates](https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2012-r2-and-2012/dn265983(v=ws.11)), and macOS requires Certificate Transparency validation for some certificates with complex rules for when it's required. Option b) (using native library just to verify certs) is probably feasible, but it would miss aspects of TLS policy other than trusted certs (like allowed algorithms), and in any case it might well require writing more code, not less, compared to using the native library for everything. So I ended up at option c), using the native library for everything. What I'd *really* prefer would be to use a third-party library that does option c) for me. Rust has a good library for this, [native-tls](https://docs.rs/native-tls/latest/native_tls/). I did search, but I couldn't find a good option in the C or C++ ecosystem, at least not any that wasn't part of some much larger framework. I was surprised - isn't this a pretty common use case? Well, many applications only need TLS for HTTPS, and they can use libcurl, which has a TLS abstraction layer internally but doesn't expose it. Other applications only support a single TLS library, or use one of the aforementioned larger frameworks, or are platform-specific to begin with, or of course are written in a non-C/C++ language, most of which have some canonical choice for TLS. But there are also many applications that have a set of TLS backends just like this; it's just that nobody has gone ahead and abstracted the pattern into a library, at least not a widespread one. Amusingly, there is one TLS abstraction layer that Yuzu already bundles: the one in ffmpeg. But it is missing some features that would be needed to use it here (like reusing an existing socket rather than managing the socket itself). Though, that does mean that the wiki's build instructions for Linux (and macOS for some reason?) already recommend installing OpenSSL, so no need to update those. ## Other APIs implemented - Sockets: - GetSockOpt(`SO_ERROR`) - SetSockOpt(`SO_NOSIGPIPE`) (stub, I have no idea what this does on Switch) - `DuplicateSocket` (because the SSL sysmodule calls it internally) - More `PollEvents` values - NSD: - `Resolve` and `ResolveEx` (stub, good enough for Open Course World and probably most third-party servers, but not first-party) - SFDNSRES: - `GetHostByNameRequest` and `GetHostByNameRequestWithOptions` - `ResolverSetOptionRequest` (stub) ## Fixes - Parts of the socket code were previously allocating a `sockaddr` object on the stack when calling functions that take a `sockaddr*` (e.g. `accept`). This might seem like the right thing to do to avoid illegal aliasing, but in fact `sockaddr` is not guaranteed to be large enough to hold any particular type of address, only the header. This worked in practice because in practice `sockaddr` is the same size as `sockaddr_in`, but it's not how the API is meant to be used. I changed this to allocate an `sockaddr_in` on the stack and `reinterpret_cast` it. I could try to do something cleverer with `aligned_storage`, but casting is the idiomatic way to use these particular APIs, so it's really the system's responsibility to avoid any aliasing issues. - I rewrote most of the `GetAddrInfoRequest[WithOptions]` implementation. The old implementation invoked the host's getaddrinfo directly from sfdnsres.cpp, and directly passed through the host's socket type, protocol, etc. values rather than looking up the corresponding constants on the Switch. To be fair, these constants don't tend to actually vary across systems, but still... I added a wrapper for `getaddrinfo` in `internal_network/network.cpp` similar to the ones for other socket APIs, and changed the `GetAddrInfoRequest` implementation to use it. While I was at it, I rewrote the serialization to use the same approach I used to implement `GetHostByNameRequest`, because it reduces the number of size calculations. While doing so I removed `AF_INET6` support because the Switch doesn't support IPv6; it might be nice to support IPv6 anyway, but that would have to apply to all of the socket APIs. I also corrected the IPC wrappers for `GetAddrInfoRequest` and `GetAddrInfoRequestWithOptions` based on reverse engineering and hardware testing. Every call to `GetAddrInfoRequestWithOptions` returns *four* different error codes (IPC status, getaddrinfo error code, netdb error code, and errno), and `GetAddrInfoRequest` returns three of those but in a different order, and it doesn't really matter but the existing implementation was a bit off, as I discovered while testing `GetHostByNameRequest`. - The new serialization code is based on two simple helper functions: ```cpp template <typename T> static void Append(std::vector<u8>& vec, T t); void AppendNulTerminated(std::vector<u8>& vec, std::string_view str); ``` I was thinking there must be existing functions somewhere that assist with serialization/deserialization of binary data, but all I could find was the helper methods in `IOFile` and `HLERequestContext`, not anything that could be used with a generic byte buffer. If I'm not missing something, then maybe I should move the above functions to a new header in `common`... right now they're just sitting in `sfdnsres.cpp` where they're used. - Not a fix, but `SocketBase::Recv`/`Send` is changed to use `std::span<u8>` rather than `std::vector<u8>&` to avoid needing to copy the data to/from a vector when those methods are called from the TLS implementation.
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#include "common/expected.h"
#include "common/socket_types.h"
#include "core/hle/service/service.h"
#include "core/hle/service/sockets/sockets.h"
#include "network/network.h"
namespace Core {
class System;
}
namespace Network {
class SocketBase;
class Socket;
} // namespace Network
namespace Service::Sockets {
class BSD final : public ServiceFramework<BSD> {
public:
explicit BSD(Core::System& system_, const char* name);
hle/service: Default constructors and destructors in the cpp file where applicable When a destructor isn't defaulted into a cpp file, it can cause the use of forward declarations to seemingly fail to compile for non-obvious reasons. It also allows inlining of the construction/destruction logic all over the place where a constructor or destructor is invoked, which can lead to code bloat. This isn't so much a worry here, given the services won't be created and destroyed frequently. The cause of the above mentioned non-obvious errors can be demonstrated as follows: ------- Demonstrative example, if you know how the described error happens, skip forwards ------- Assume we have the following in the header, which we'll call "thing.h": \#include <memory> // Forward declaration. For example purposes, assume the definition // of Object is in some header named "object.h" class Object; class Thing { public: // assume no constructors or destructors are specified here, // or the constructors/destructors are defined as: // // Thing() = default; // ~Thing() = default; // // ... Some interface member functions would be defined here private: std::shared_ptr<Object> obj; }; If this header is included in a cpp file, (which we'll call "main.cpp"), this will result in a compilation error, because even though no destructor is specified, the destructor will still need to be generated by the compiler because std::shared_ptr's destructor is *not* trivial (in other words, it does something other than nothing), as std::shared_ptr's destructor needs to do two things: 1. Decrement the shared reference count of the object being pointed to, and if the reference count decrements to zero, 2. Free the Object instance's memory (aka deallocate the memory it's pointing to). And so the compiler generates the code for the destructor doing this inside main.cpp. Now, keep in mind, the Object forward declaration is not a complete type. All it does is tell the compiler "a type named Object exists" and allows us to use the name in certain situations to avoid a header dependency. So the compiler needs to generate destruction code for Object, but the compiler doesn't know *how* to destruct it. A forward declaration doesn't tell the compiler anything about Object's constructor or destructor. So, the compiler will issue an error in this case because it's undefined behavior to try and deallocate (or construct) an incomplete type and std::shared_ptr and std::unique_ptr make sure this isn't the case internally. Now, if we had defaulted the destructor in "thing.cpp", where we also include "object.h", this would never be an issue, as the destructor would only have its code generated in one place, and it would be in a place where the full class definition of Object would be visible to the compiler. ---------------------- End example ---------------------------- Given these service classes are more than certainly going to change in the future, this defaults the constructors and destructors into the relevant cpp files to make the construction and destruction of all of the services consistent and unlikely to run into cases where forward declarations are indirectly causing compilation errors. It also has the plus of avoiding the need to rebuild several services if destruction logic changes, since it would only be necessary to recompile the single cpp file.
2018-09-11 01:20:52 +00:00
~BSD() override;
Implement SSL service This implements some missing network APIs including a large chunk of the SSL service, enough for Mario Maker (with an appropriate mod applied) to connect to the fan server [Open Course World](https://opencourse.world/). Connecting to first-party servers is out of scope of this PR and is a minefield I'd rather not step into. ## TLS TLS is implemented with multiple backends depending on the system's 'native' TLS library. Currently there are two backends: Schannel for Windows, and OpenSSL for Linux. (In reality Linux is a bit of a free-for-all where there's no one 'native' library, but OpenSSL is the closest it gets.) On macOS the 'native' library is SecureTransport but that isn't implemented in this PR. (Instead, all non-Windows OSes will use OpenSSL unless disabled with `-DENABLE_OPENSSL=OFF`.) Why have multiple backends instead of just using a single library, especially given that Yuzu already embeds mbedtls for cryptographic algorithms? Well, I tried implementing this on mbedtls first, but the problem is TLS policies - mainly trusted certificate policies, and to a lesser extent trusted algorithms, SSL versions, etc. ...In practice, the chance that someone is going to conduct a man-in-the-middle attack on a third-party game server is pretty low, but I'm a security nerd so I like to do the right security things. My base assumption is that we want to use the host system's TLS policies. An alternative would be to more closely emulate the Switch's TLS implementation (which is based on NSS). But for one thing, I don't feel like reverse engineering it. And I'd argue that for third-party servers such as Open Course World, it's theoretically preferable to use the system's policies rather than the Switch's, for two reasons 1. Someday the Switch will stop being updated, and the trusted cert list, algorithms, etc. will start to go stale, but users will still want to connect to third-party servers, and there's no reason they shouldn't have up-to-date security when doing so. At that point, homebrew users on actual hardware may patch the TLS implementation, but for emulators it's simpler to just use the host's stack. 2. Also, it's good to respect any custom certificate policies the user may have added systemwide. For example, they may have added custom trusted CAs in order to use TLS debugging tools or pass through corporate MitM middleboxes. Or they may have removed some CAs that are normally trusted out of paranoia. Note that this policy wouldn't work as-is for connecting to first-party servers, because some of them serve certificates based on Nintendo's own CA rather than a publicly trusted one. However, this could probably be solved easily by using appropriate APIs to adding Nintendo's CA as an alternate trusted cert for Yuzu's connections. That is not implemented in this PR because, again, first-party servers are out of scope. (If anything I'd rather have an option to _block_ connections to Nintendo servers, but that's not implemented here.) To use the host's TLS policies, there are three theoretical options: a) Import the host's trusted certificate list into a cross-platform TLS library (presumably mbedtls). b) Use the native TLS library to verify certificates but use a cross-platform TLS library for everything else. c) Use the native TLS library for everything. Two problems with option a). First, importing the trusted certificate list at minimum requires a bunch of platform-specific code, which mbedtls does not have built in. Interestingly, OpenSSL recently gained the ability to import the Windows certificate trust store... but that leads to the second problem, which is that a list of trusted certificates is [not expressive enough](https://bugs.archlinux.org/task/41909) to express a modern certificate trust policy. For example, Windows has the concept of [explicitly distrusted certificates](https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2012-r2-and-2012/dn265983(v=ws.11)), and macOS requires Certificate Transparency validation for some certificates with complex rules for when it's required. Option b) (using native library just to verify certs) is probably feasible, but it would miss aspects of TLS policy other than trusted certs (like allowed algorithms), and in any case it might well require writing more code, not less, compared to using the native library for everything. So I ended up at option c), using the native library for everything. What I'd *really* prefer would be to use a third-party library that does option c) for me. Rust has a good library for this, [native-tls](https://docs.rs/native-tls/latest/native_tls/). I did search, but I couldn't find a good option in the C or C++ ecosystem, at least not any that wasn't part of some much larger framework. I was surprised - isn't this a pretty common use case? Well, many applications only need TLS for HTTPS, and they can use libcurl, which has a TLS abstraction layer internally but doesn't expose it. Other applications only support a single TLS library, or use one of the aforementioned larger frameworks, or are platform-specific to begin with, or of course are written in a non-C/C++ language, most of which have some canonical choice for TLS. But there are also many applications that have a set of TLS backends just like this; it's just that nobody has gone ahead and abstracted the pattern into a library, at least not a widespread one. Amusingly, there is one TLS abstraction layer that Yuzu already bundles: the one in ffmpeg. But it is missing some features that would be needed to use it here (like reusing an existing socket rather than managing the socket itself). Though, that does mean that the wiki's build instructions for Linux (and macOS for some reason?) already recommend installing OpenSSL, so no need to update those. ## Other APIs implemented - Sockets: - GetSockOpt(`SO_ERROR`) - SetSockOpt(`SO_NOSIGPIPE`) (stub, I have no idea what this does on Switch) - `DuplicateSocket` (because the SSL sysmodule calls it internally) - More `PollEvents` values - NSD: - `Resolve` and `ResolveEx` (stub, good enough for Open Course World and probably most third-party servers, but not first-party) - SFDNSRES: - `GetHostByNameRequest` and `GetHostByNameRequestWithOptions` - `ResolverSetOptionRequest` (stub) ## Fixes - Parts of the socket code were previously allocating a `sockaddr` object on the stack when calling functions that take a `sockaddr*` (e.g. `accept`). This might seem like the right thing to do to avoid illegal aliasing, but in fact `sockaddr` is not guaranteed to be large enough to hold any particular type of address, only the header. This worked in practice because in practice `sockaddr` is the same size as `sockaddr_in`, but it's not how the API is meant to be used. I changed this to allocate an `sockaddr_in` on the stack and `reinterpret_cast` it. I could try to do something cleverer with `aligned_storage`, but casting is the idiomatic way to use these particular APIs, so it's really the system's responsibility to avoid any aliasing issues. - I rewrote most of the `GetAddrInfoRequest[WithOptions]` implementation. The old implementation invoked the host's getaddrinfo directly from sfdnsres.cpp, and directly passed through the host's socket type, protocol, etc. values rather than looking up the corresponding constants on the Switch. To be fair, these constants don't tend to actually vary across systems, but still... I added a wrapper for `getaddrinfo` in `internal_network/network.cpp` similar to the ones for other socket APIs, and changed the `GetAddrInfoRequest` implementation to use it. While I was at it, I rewrote the serialization to use the same approach I used to implement `GetHostByNameRequest`, because it reduces the number of size calculations. While doing so I removed `AF_INET6` support because the Switch doesn't support IPv6; it might be nice to support IPv6 anyway, but that would have to apply to all of the socket APIs. I also corrected the IPC wrappers for `GetAddrInfoRequest` and `GetAddrInfoRequestWithOptions` based on reverse engineering and hardware testing. Every call to `GetAddrInfoRequestWithOptions` returns *four* different error codes (IPC status, getaddrinfo error code, netdb error code, and errno), and `GetAddrInfoRequest` returns three of those but in a different order, and it doesn't really matter but the existing implementation was a bit off, as I discovered while testing `GetHostByNameRequest`. - The new serialization code is based on two simple helper functions: ```cpp template <typename T> static void Append(std::vector<u8>& vec, T t); void AppendNulTerminated(std::vector<u8>& vec, std::string_view str); ``` I was thinking there must be existing functions somewhere that assist with serialization/deserialization of binary data, but all I could find was the helper methods in `IOFile` and `HLERequestContext`, not anything that could be used with a generic byte buffer. If I'm not missing something, then maybe I should move the above functions to a new header in `common`... right now they're just sitting in `sfdnsres.cpp` where they're used. - Not a fix, but `SocketBase::Recv`/`Send` is changed to use `std::span<u8>` rather than `std::vector<u8>&` to avoid needing to copy the data to/from a vector when those methods are called from the TLS implementation.
2023-06-20 01:17:43 +00:00
// These methods are called from SSL; the first two are also called from
// this class for the corresponding IPC methods.
// On the real device, the SSL service makes IPC calls to this service.
Common::Expected<s32, Errno> DuplicateSocketImpl(s32 fd);
Errno CloseImpl(s32 fd);
std::optional<std::shared_ptr<Network::SocketBase>> GetSocket(s32 fd);
private:
/// Maximum number of file descriptors
static constexpr size_t MAX_FD = 128;
struct FileDescriptor {
Implement SSL service This implements some missing network APIs including a large chunk of the SSL service, enough for Mario Maker (with an appropriate mod applied) to connect to the fan server [Open Course World](https://opencourse.world/). Connecting to first-party servers is out of scope of this PR and is a minefield I'd rather not step into. ## TLS TLS is implemented with multiple backends depending on the system's 'native' TLS library. Currently there are two backends: Schannel for Windows, and OpenSSL for Linux. (In reality Linux is a bit of a free-for-all where there's no one 'native' library, but OpenSSL is the closest it gets.) On macOS the 'native' library is SecureTransport but that isn't implemented in this PR. (Instead, all non-Windows OSes will use OpenSSL unless disabled with `-DENABLE_OPENSSL=OFF`.) Why have multiple backends instead of just using a single library, especially given that Yuzu already embeds mbedtls for cryptographic algorithms? Well, I tried implementing this on mbedtls first, but the problem is TLS policies - mainly trusted certificate policies, and to a lesser extent trusted algorithms, SSL versions, etc. ...In practice, the chance that someone is going to conduct a man-in-the-middle attack on a third-party game server is pretty low, but I'm a security nerd so I like to do the right security things. My base assumption is that we want to use the host system's TLS policies. An alternative would be to more closely emulate the Switch's TLS implementation (which is based on NSS). But for one thing, I don't feel like reverse engineering it. And I'd argue that for third-party servers such as Open Course World, it's theoretically preferable to use the system's policies rather than the Switch's, for two reasons 1. Someday the Switch will stop being updated, and the trusted cert list, algorithms, etc. will start to go stale, but users will still want to connect to third-party servers, and there's no reason they shouldn't have up-to-date security when doing so. At that point, homebrew users on actual hardware may patch the TLS implementation, but for emulators it's simpler to just use the host's stack. 2. Also, it's good to respect any custom certificate policies the user may have added systemwide. For example, they may have added custom trusted CAs in order to use TLS debugging tools or pass through corporate MitM middleboxes. Or they may have removed some CAs that are normally trusted out of paranoia. Note that this policy wouldn't work as-is for connecting to first-party servers, because some of them serve certificates based on Nintendo's own CA rather than a publicly trusted one. However, this could probably be solved easily by using appropriate APIs to adding Nintendo's CA as an alternate trusted cert for Yuzu's connections. That is not implemented in this PR because, again, first-party servers are out of scope. (If anything I'd rather have an option to _block_ connections to Nintendo servers, but that's not implemented here.) To use the host's TLS policies, there are three theoretical options: a) Import the host's trusted certificate list into a cross-platform TLS library (presumably mbedtls). b) Use the native TLS library to verify certificates but use a cross-platform TLS library for everything else. c) Use the native TLS library for everything. Two problems with option a). First, importing the trusted certificate list at minimum requires a bunch of platform-specific code, which mbedtls does not have built in. Interestingly, OpenSSL recently gained the ability to import the Windows certificate trust store... but that leads to the second problem, which is that a list of trusted certificates is [not expressive enough](https://bugs.archlinux.org/task/41909) to express a modern certificate trust policy. For example, Windows has the concept of [explicitly distrusted certificates](https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2012-r2-and-2012/dn265983(v=ws.11)), and macOS requires Certificate Transparency validation for some certificates with complex rules for when it's required. Option b) (using native library just to verify certs) is probably feasible, but it would miss aspects of TLS policy other than trusted certs (like allowed algorithms), and in any case it might well require writing more code, not less, compared to using the native library for everything. So I ended up at option c), using the native library for everything. What I'd *really* prefer would be to use a third-party library that does option c) for me. Rust has a good library for this, [native-tls](https://docs.rs/native-tls/latest/native_tls/). I did search, but I couldn't find a good option in the C or C++ ecosystem, at least not any that wasn't part of some much larger framework. I was surprised - isn't this a pretty common use case? Well, many applications only need TLS for HTTPS, and they can use libcurl, which has a TLS abstraction layer internally but doesn't expose it. Other applications only support a single TLS library, or use one of the aforementioned larger frameworks, or are platform-specific to begin with, or of course are written in a non-C/C++ language, most of which have some canonical choice for TLS. But there are also many applications that have a set of TLS backends just like this; it's just that nobody has gone ahead and abstracted the pattern into a library, at least not a widespread one. Amusingly, there is one TLS abstraction layer that Yuzu already bundles: the one in ffmpeg. But it is missing some features that would be needed to use it here (like reusing an existing socket rather than managing the socket itself). Though, that does mean that the wiki's build instructions for Linux (and macOS for some reason?) already recommend installing OpenSSL, so no need to update those. ## Other APIs implemented - Sockets: - GetSockOpt(`SO_ERROR`) - SetSockOpt(`SO_NOSIGPIPE`) (stub, I have no idea what this does on Switch) - `DuplicateSocket` (because the SSL sysmodule calls it internally) - More `PollEvents` values - NSD: - `Resolve` and `ResolveEx` (stub, good enough for Open Course World and probably most third-party servers, but not first-party) - SFDNSRES: - `GetHostByNameRequest` and `GetHostByNameRequestWithOptions` - `ResolverSetOptionRequest` (stub) ## Fixes - Parts of the socket code were previously allocating a `sockaddr` object on the stack when calling functions that take a `sockaddr*` (e.g. `accept`). This might seem like the right thing to do to avoid illegal aliasing, but in fact `sockaddr` is not guaranteed to be large enough to hold any particular type of address, only the header. This worked in practice because in practice `sockaddr` is the same size as `sockaddr_in`, but it's not how the API is meant to be used. I changed this to allocate an `sockaddr_in` on the stack and `reinterpret_cast` it. I could try to do something cleverer with `aligned_storage`, but casting is the idiomatic way to use these particular APIs, so it's really the system's responsibility to avoid any aliasing issues. - I rewrote most of the `GetAddrInfoRequest[WithOptions]` implementation. The old implementation invoked the host's getaddrinfo directly from sfdnsres.cpp, and directly passed through the host's socket type, protocol, etc. values rather than looking up the corresponding constants on the Switch. To be fair, these constants don't tend to actually vary across systems, but still... I added a wrapper for `getaddrinfo` in `internal_network/network.cpp` similar to the ones for other socket APIs, and changed the `GetAddrInfoRequest` implementation to use it. While I was at it, I rewrote the serialization to use the same approach I used to implement `GetHostByNameRequest`, because it reduces the number of size calculations. While doing so I removed `AF_INET6` support because the Switch doesn't support IPv6; it might be nice to support IPv6 anyway, but that would have to apply to all of the socket APIs. I also corrected the IPC wrappers for `GetAddrInfoRequest` and `GetAddrInfoRequestWithOptions` based on reverse engineering and hardware testing. Every call to `GetAddrInfoRequestWithOptions` returns *four* different error codes (IPC status, getaddrinfo error code, netdb error code, and errno), and `GetAddrInfoRequest` returns three of those but in a different order, and it doesn't really matter but the existing implementation was a bit off, as I discovered while testing `GetHostByNameRequest`. - The new serialization code is based on two simple helper functions: ```cpp template <typename T> static void Append(std::vector<u8>& vec, T t); void AppendNulTerminated(std::vector<u8>& vec, std::string_view str); ``` I was thinking there must be existing functions somewhere that assist with serialization/deserialization of binary data, but all I could find was the helper methods in `IOFile` and `HLERequestContext`, not anything that could be used with a generic byte buffer. If I'm not missing something, then maybe I should move the above functions to a new header in `common`... right now they're just sitting in `sfdnsres.cpp` where they're used. - Not a fix, but `SocketBase::Recv`/`Send` is changed to use `std::span<u8>` rather than `std::vector<u8>&` to avoid needing to copy the data to/from a vector when those methods are called from the TLS implementation.
2023-06-20 01:17:43 +00:00
std::shared_ptr<Network::SocketBase> socket;
s32 flags = 0;
bool is_connection_based = false;
};
struct PollWork {
void Execute(BSD* bsd);
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void Response(HLERequestContext& ctx);
s32 nfds;
s32 timeout;
std::span<const u8> read_buffer;
std::vector<u8> write_buffer;
s32 ret{};
Errno bsd_errno{};
};
struct AcceptWork {
void Execute(BSD* bsd);
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void Response(HLERequestContext& ctx);
s32 fd;
std::vector<u8> write_buffer;
s32 ret{};
Errno bsd_errno{};
};
struct ConnectWork {
void Execute(BSD* bsd);
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void Response(HLERequestContext& ctx);
s32 fd;
std::span<const u8> addr;
Errno bsd_errno{};
};
struct RecvWork {
void Execute(BSD* bsd);
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void Response(HLERequestContext& ctx);
s32 fd;
u32 flags;
std::vector<u8> message;
s32 ret{};
Errno bsd_errno{};
};
struct RecvFromWork {
void Execute(BSD* bsd);
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void Response(HLERequestContext& ctx);
s32 fd;
u32 flags;
std::vector<u8> message;
std::vector<u8> addr;
s32 ret{};
Errno bsd_errno{};
};
struct SendWork {
void Execute(BSD* bsd);
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void Response(HLERequestContext& ctx);
s32 fd;
u32 flags;
std::span<const u8> message;
s32 ret{};
Errno bsd_errno{};
};
struct SendToWork {
void Execute(BSD* bsd);
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void Response(HLERequestContext& ctx);
s32 fd;
u32 flags;
std::span<const u8> message;
std::span<const u8> addr;
s32 ret{};
Errno bsd_errno{};
};
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void RegisterClient(HLERequestContext& ctx);
void StartMonitoring(HLERequestContext& ctx);
void Socket(HLERequestContext& ctx);
void Select(HLERequestContext& ctx);
void Poll(HLERequestContext& ctx);
void Accept(HLERequestContext& ctx);
void Bind(HLERequestContext& ctx);
void Connect(HLERequestContext& ctx);
void GetPeerName(HLERequestContext& ctx);
void GetSockName(HLERequestContext& ctx);
void GetSockOpt(HLERequestContext& ctx);
void Listen(HLERequestContext& ctx);
void Fcntl(HLERequestContext& ctx);
void SetSockOpt(HLERequestContext& ctx);
void Shutdown(HLERequestContext& ctx);
void Recv(HLERequestContext& ctx);
void RecvFrom(HLERequestContext& ctx);
void Send(HLERequestContext& ctx);
void SendTo(HLERequestContext& ctx);
void Write(HLERequestContext& ctx);
void Read(HLERequestContext& ctx);
void Close(HLERequestContext& ctx);
Implement SSL service This implements some missing network APIs including a large chunk of the SSL service, enough for Mario Maker (with an appropriate mod applied) to connect to the fan server [Open Course World](https://opencourse.world/). Connecting to first-party servers is out of scope of this PR and is a minefield I'd rather not step into. ## TLS TLS is implemented with multiple backends depending on the system's 'native' TLS library. Currently there are two backends: Schannel for Windows, and OpenSSL for Linux. (In reality Linux is a bit of a free-for-all where there's no one 'native' library, but OpenSSL is the closest it gets.) On macOS the 'native' library is SecureTransport but that isn't implemented in this PR. (Instead, all non-Windows OSes will use OpenSSL unless disabled with `-DENABLE_OPENSSL=OFF`.) Why have multiple backends instead of just using a single library, especially given that Yuzu already embeds mbedtls for cryptographic algorithms? Well, I tried implementing this on mbedtls first, but the problem is TLS policies - mainly trusted certificate policies, and to a lesser extent trusted algorithms, SSL versions, etc. ...In practice, the chance that someone is going to conduct a man-in-the-middle attack on a third-party game server is pretty low, but I'm a security nerd so I like to do the right security things. My base assumption is that we want to use the host system's TLS policies. An alternative would be to more closely emulate the Switch's TLS implementation (which is based on NSS). But for one thing, I don't feel like reverse engineering it. And I'd argue that for third-party servers such as Open Course World, it's theoretically preferable to use the system's policies rather than the Switch's, for two reasons 1. Someday the Switch will stop being updated, and the trusted cert list, algorithms, etc. will start to go stale, but users will still want to connect to third-party servers, and there's no reason they shouldn't have up-to-date security when doing so. At that point, homebrew users on actual hardware may patch the TLS implementation, but for emulators it's simpler to just use the host's stack. 2. Also, it's good to respect any custom certificate policies the user may have added systemwide. For example, they may have added custom trusted CAs in order to use TLS debugging tools or pass through corporate MitM middleboxes. Or they may have removed some CAs that are normally trusted out of paranoia. Note that this policy wouldn't work as-is for connecting to first-party servers, because some of them serve certificates based on Nintendo's own CA rather than a publicly trusted one. However, this could probably be solved easily by using appropriate APIs to adding Nintendo's CA as an alternate trusted cert for Yuzu's connections. That is not implemented in this PR because, again, first-party servers are out of scope. (If anything I'd rather have an option to _block_ connections to Nintendo servers, but that's not implemented here.) To use the host's TLS policies, there are three theoretical options: a) Import the host's trusted certificate list into a cross-platform TLS library (presumably mbedtls). b) Use the native TLS library to verify certificates but use a cross-platform TLS library for everything else. c) Use the native TLS library for everything. Two problems with option a). First, importing the trusted certificate list at minimum requires a bunch of platform-specific code, which mbedtls does not have built in. Interestingly, OpenSSL recently gained the ability to import the Windows certificate trust store... but that leads to the second problem, which is that a list of trusted certificates is [not expressive enough](https://bugs.archlinux.org/task/41909) to express a modern certificate trust policy. For example, Windows has the concept of [explicitly distrusted certificates](https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2012-r2-and-2012/dn265983(v=ws.11)), and macOS requires Certificate Transparency validation for some certificates with complex rules for when it's required. Option b) (using native library just to verify certs) is probably feasible, but it would miss aspects of TLS policy other than trusted certs (like allowed algorithms), and in any case it might well require writing more code, not less, compared to using the native library for everything. So I ended up at option c), using the native library for everything. What I'd *really* prefer would be to use a third-party library that does option c) for me. Rust has a good library for this, [native-tls](https://docs.rs/native-tls/latest/native_tls/). I did search, but I couldn't find a good option in the C or C++ ecosystem, at least not any that wasn't part of some much larger framework. I was surprised - isn't this a pretty common use case? Well, many applications only need TLS for HTTPS, and they can use libcurl, which has a TLS abstraction layer internally but doesn't expose it. Other applications only support a single TLS library, or use one of the aforementioned larger frameworks, or are platform-specific to begin with, or of course are written in a non-C/C++ language, most of which have some canonical choice for TLS. But there are also many applications that have a set of TLS backends just like this; it's just that nobody has gone ahead and abstracted the pattern into a library, at least not a widespread one. Amusingly, there is one TLS abstraction layer that Yuzu already bundles: the one in ffmpeg. But it is missing some features that would be needed to use it here (like reusing an existing socket rather than managing the socket itself). Though, that does mean that the wiki's build instructions for Linux (and macOS for some reason?) already recommend installing OpenSSL, so no need to update those. ## Other APIs implemented - Sockets: - GetSockOpt(`SO_ERROR`) - SetSockOpt(`SO_NOSIGPIPE`) (stub, I have no idea what this does on Switch) - `DuplicateSocket` (because the SSL sysmodule calls it internally) - More `PollEvents` values - NSD: - `Resolve` and `ResolveEx` (stub, good enough for Open Course World and probably most third-party servers, but not first-party) - SFDNSRES: - `GetHostByNameRequest` and `GetHostByNameRequestWithOptions` - `ResolverSetOptionRequest` (stub) ## Fixes - Parts of the socket code were previously allocating a `sockaddr` object on the stack when calling functions that take a `sockaddr*` (e.g. `accept`). This might seem like the right thing to do to avoid illegal aliasing, but in fact `sockaddr` is not guaranteed to be large enough to hold any particular type of address, only the header. This worked in practice because in practice `sockaddr` is the same size as `sockaddr_in`, but it's not how the API is meant to be used. I changed this to allocate an `sockaddr_in` on the stack and `reinterpret_cast` it. I could try to do something cleverer with `aligned_storage`, but casting is the idiomatic way to use these particular APIs, so it's really the system's responsibility to avoid any aliasing issues. - I rewrote most of the `GetAddrInfoRequest[WithOptions]` implementation. The old implementation invoked the host's getaddrinfo directly from sfdnsres.cpp, and directly passed through the host's socket type, protocol, etc. values rather than looking up the corresponding constants on the Switch. To be fair, these constants don't tend to actually vary across systems, but still... I added a wrapper for `getaddrinfo` in `internal_network/network.cpp` similar to the ones for other socket APIs, and changed the `GetAddrInfoRequest` implementation to use it. While I was at it, I rewrote the serialization to use the same approach I used to implement `GetHostByNameRequest`, because it reduces the number of size calculations. While doing so I removed `AF_INET6` support because the Switch doesn't support IPv6; it might be nice to support IPv6 anyway, but that would have to apply to all of the socket APIs. I also corrected the IPC wrappers for `GetAddrInfoRequest` and `GetAddrInfoRequestWithOptions` based on reverse engineering and hardware testing. Every call to `GetAddrInfoRequestWithOptions` returns *four* different error codes (IPC status, getaddrinfo error code, netdb error code, and errno), and `GetAddrInfoRequest` returns three of those but in a different order, and it doesn't really matter but the existing implementation was a bit off, as I discovered while testing `GetHostByNameRequest`. - The new serialization code is based on two simple helper functions: ```cpp template <typename T> static void Append(std::vector<u8>& vec, T t); void AppendNulTerminated(std::vector<u8>& vec, std::string_view str); ``` I was thinking there must be existing functions somewhere that assist with serialization/deserialization of binary data, but all I could find was the helper methods in `IOFile` and `HLERequestContext`, not anything that could be used with a generic byte buffer. If I'm not missing something, then maybe I should move the above functions to a new header in `common`... right now they're just sitting in `sfdnsres.cpp` where they're used. - Not a fix, but `SocketBase::Recv`/`Send` is changed to use `std::span<u8>` rather than `std::vector<u8>&` to avoid needing to copy the data to/from a vector when those methods are called from the TLS implementation.
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void DuplicateSocket(HLERequestContext& ctx);
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void EventFd(HLERequestContext& ctx);
template <typename Work>
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void ExecuteWork(HLERequestContext& ctx, Work work);
std::pair<s32, Errno> SocketImpl(Domain domain, Type type, Protocol protocol);
std::pair<s32, Errno> PollImpl(std::vector<u8>& write_buffer, std::span<const u8> read_buffer,
s32 nfds, s32 timeout);
std::pair<s32, Errno> AcceptImpl(s32 fd, std::vector<u8>& write_buffer);
Errno BindImpl(s32 fd, std::span<const u8> addr);
Errno ConnectImpl(s32 fd, std::span<const u8> addr);
Errno GetPeerNameImpl(s32 fd, std::vector<u8>& write_buffer);
Errno GetSockNameImpl(s32 fd, std::vector<u8>& write_buffer);
Errno ListenImpl(s32 fd, s32 backlog);
std::pair<s32, Errno> FcntlImpl(s32 fd, FcntlCmd cmd, s32 arg);
Implement SSL service This implements some missing network APIs including a large chunk of the SSL service, enough for Mario Maker (with an appropriate mod applied) to connect to the fan server [Open Course World](https://opencourse.world/). Connecting to first-party servers is out of scope of this PR and is a minefield I'd rather not step into. ## TLS TLS is implemented with multiple backends depending on the system's 'native' TLS library. Currently there are two backends: Schannel for Windows, and OpenSSL for Linux. (In reality Linux is a bit of a free-for-all where there's no one 'native' library, but OpenSSL is the closest it gets.) On macOS the 'native' library is SecureTransport but that isn't implemented in this PR. (Instead, all non-Windows OSes will use OpenSSL unless disabled with `-DENABLE_OPENSSL=OFF`.) Why have multiple backends instead of just using a single library, especially given that Yuzu already embeds mbedtls for cryptographic algorithms? Well, I tried implementing this on mbedtls first, but the problem is TLS policies - mainly trusted certificate policies, and to a lesser extent trusted algorithms, SSL versions, etc. ...In practice, the chance that someone is going to conduct a man-in-the-middle attack on a third-party game server is pretty low, but I'm a security nerd so I like to do the right security things. My base assumption is that we want to use the host system's TLS policies. An alternative would be to more closely emulate the Switch's TLS implementation (which is based on NSS). But for one thing, I don't feel like reverse engineering it. And I'd argue that for third-party servers such as Open Course World, it's theoretically preferable to use the system's policies rather than the Switch's, for two reasons 1. Someday the Switch will stop being updated, and the trusted cert list, algorithms, etc. will start to go stale, but users will still want to connect to third-party servers, and there's no reason they shouldn't have up-to-date security when doing so. At that point, homebrew users on actual hardware may patch the TLS implementation, but for emulators it's simpler to just use the host's stack. 2. Also, it's good to respect any custom certificate policies the user may have added systemwide. For example, they may have added custom trusted CAs in order to use TLS debugging tools or pass through corporate MitM middleboxes. Or they may have removed some CAs that are normally trusted out of paranoia. Note that this policy wouldn't work as-is for connecting to first-party servers, because some of them serve certificates based on Nintendo's own CA rather than a publicly trusted one. However, this could probably be solved easily by using appropriate APIs to adding Nintendo's CA as an alternate trusted cert for Yuzu's connections. That is not implemented in this PR because, again, first-party servers are out of scope. (If anything I'd rather have an option to _block_ connections to Nintendo servers, but that's not implemented here.) To use the host's TLS policies, there are three theoretical options: a) Import the host's trusted certificate list into a cross-platform TLS library (presumably mbedtls). b) Use the native TLS library to verify certificates but use a cross-platform TLS library for everything else. c) Use the native TLS library for everything. Two problems with option a). First, importing the trusted certificate list at minimum requires a bunch of platform-specific code, which mbedtls does not have built in. Interestingly, OpenSSL recently gained the ability to import the Windows certificate trust store... but that leads to the second problem, which is that a list of trusted certificates is [not expressive enough](https://bugs.archlinux.org/task/41909) to express a modern certificate trust policy. For example, Windows has the concept of [explicitly distrusted certificates](https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2012-r2-and-2012/dn265983(v=ws.11)), and macOS requires Certificate Transparency validation for some certificates with complex rules for when it's required. Option b) (using native library just to verify certs) is probably feasible, but it would miss aspects of TLS policy other than trusted certs (like allowed algorithms), and in any case it might well require writing more code, not less, compared to using the native library for everything. So I ended up at option c), using the native library for everything. What I'd *really* prefer would be to use a third-party library that does option c) for me. Rust has a good library for this, [native-tls](https://docs.rs/native-tls/latest/native_tls/). I did search, but I couldn't find a good option in the C or C++ ecosystem, at least not any that wasn't part of some much larger framework. I was surprised - isn't this a pretty common use case? Well, many applications only need TLS for HTTPS, and they can use libcurl, which has a TLS abstraction layer internally but doesn't expose it. Other applications only support a single TLS library, or use one of the aforementioned larger frameworks, or are platform-specific to begin with, or of course are written in a non-C/C++ language, most of which have some canonical choice for TLS. But there are also many applications that have a set of TLS backends just like this; it's just that nobody has gone ahead and abstracted the pattern into a library, at least not a widespread one. Amusingly, there is one TLS abstraction layer that Yuzu already bundles: the one in ffmpeg. But it is missing some features that would be needed to use it here (like reusing an existing socket rather than managing the socket itself). Though, that does mean that the wiki's build instructions for Linux (and macOS for some reason?) already recommend installing OpenSSL, so no need to update those. ## Other APIs implemented - Sockets: - GetSockOpt(`SO_ERROR`) - SetSockOpt(`SO_NOSIGPIPE`) (stub, I have no idea what this does on Switch) - `DuplicateSocket` (because the SSL sysmodule calls it internally) - More `PollEvents` values - NSD: - `Resolve` and `ResolveEx` (stub, good enough for Open Course World and probably most third-party servers, but not first-party) - SFDNSRES: - `GetHostByNameRequest` and `GetHostByNameRequestWithOptions` - `ResolverSetOptionRequest` (stub) ## Fixes - Parts of the socket code were previously allocating a `sockaddr` object on the stack when calling functions that take a `sockaddr*` (e.g. `accept`). This might seem like the right thing to do to avoid illegal aliasing, but in fact `sockaddr` is not guaranteed to be large enough to hold any particular type of address, only the header. This worked in practice because in practice `sockaddr` is the same size as `sockaddr_in`, but it's not how the API is meant to be used. I changed this to allocate an `sockaddr_in` on the stack and `reinterpret_cast` it. I could try to do something cleverer with `aligned_storage`, but casting is the idiomatic way to use these particular APIs, so it's really the system's responsibility to avoid any aliasing issues. - I rewrote most of the `GetAddrInfoRequest[WithOptions]` implementation. The old implementation invoked the host's getaddrinfo directly from sfdnsres.cpp, and directly passed through the host's socket type, protocol, etc. values rather than looking up the corresponding constants on the Switch. To be fair, these constants don't tend to actually vary across systems, but still... I added a wrapper for `getaddrinfo` in `internal_network/network.cpp` similar to the ones for other socket APIs, and changed the `GetAddrInfoRequest` implementation to use it. While I was at it, I rewrote the serialization to use the same approach I used to implement `GetHostByNameRequest`, because it reduces the number of size calculations. While doing so I removed `AF_INET6` support because the Switch doesn't support IPv6; it might be nice to support IPv6 anyway, but that would have to apply to all of the socket APIs. I also corrected the IPC wrappers for `GetAddrInfoRequest` and `GetAddrInfoRequestWithOptions` based on reverse engineering and hardware testing. Every call to `GetAddrInfoRequestWithOptions` returns *four* different error codes (IPC status, getaddrinfo error code, netdb error code, and errno), and `GetAddrInfoRequest` returns three of those but in a different order, and it doesn't really matter but the existing implementation was a bit off, as I discovered while testing `GetHostByNameRequest`. - The new serialization code is based on two simple helper functions: ```cpp template <typename T> static void Append(std::vector<u8>& vec, T t); void AppendNulTerminated(std::vector<u8>& vec, std::string_view str); ``` I was thinking there must be existing functions somewhere that assist with serialization/deserialization of binary data, but all I could find was the helper methods in `IOFile` and `HLERequestContext`, not anything that could be used with a generic byte buffer. If I'm not missing something, then maybe I should move the above functions to a new header in `common`... right now they're just sitting in `sfdnsres.cpp` where they're used. - Not a fix, but `SocketBase::Recv`/`Send` is changed to use `std::span<u8>` rather than `std::vector<u8>&` to avoid needing to copy the data to/from a vector when those methods are called from the TLS implementation.
2023-06-20 01:17:43 +00:00
Errno GetSockOptImpl(s32 fd, u32 level, OptName optname, std::vector<u8>& optval);
Errno SetSockOptImpl(s32 fd, u32 level, OptName optname, size_t optlen, const void* optval);
Errno ShutdownImpl(s32 fd, s32 how);
std::pair<s32, Errno> RecvImpl(s32 fd, u32 flags, std::vector<u8>& message);
std::pair<s32, Errno> RecvFromImpl(s32 fd, u32 flags, std::vector<u8>& message,
std::vector<u8>& addr);
std::pair<s32, Errno> SendImpl(s32 fd, u32 flags, std::span<const u8> message);
std::pair<s32, Errno> SendToImpl(s32 fd, u32 flags, std::span<const u8> message,
std::span<const u8> addr);
s32 FindFreeFileDescriptorHandle() noexcept;
bool IsFileDescriptorValid(s32 fd) const noexcept;
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void BuildErrnoResponse(HLERequestContext& ctx, Errno bsd_errno) const noexcept;
std::array<std::optional<FileDescriptor>, MAX_FD> file_descriptors;
Network::RoomNetwork& room_network;
/// Callback to parse and handle a received wifi packet.
void OnProxyPacketReceived(const Network::ProxyPacket& packet);
// Callback identifier for the OnProxyPacketReceived event.
Network::RoomMember::CallbackHandle<Network::ProxyPacket> proxy_packet_received;
};
class BSDCFG final : public ServiceFramework<BSDCFG> {
public:
explicit BSDCFG(Core::System& system_);
hle/service: Default constructors and destructors in the cpp file where applicable When a destructor isn't defaulted into a cpp file, it can cause the use of forward declarations to seemingly fail to compile for non-obvious reasons. It also allows inlining of the construction/destruction logic all over the place where a constructor or destructor is invoked, which can lead to code bloat. This isn't so much a worry here, given the services won't be created and destroyed frequently. The cause of the above mentioned non-obvious errors can be demonstrated as follows: ------- Demonstrative example, if you know how the described error happens, skip forwards ------- Assume we have the following in the header, which we'll call "thing.h": \#include <memory> // Forward declaration. For example purposes, assume the definition // of Object is in some header named "object.h" class Object; class Thing { public: // assume no constructors or destructors are specified here, // or the constructors/destructors are defined as: // // Thing() = default; // ~Thing() = default; // // ... Some interface member functions would be defined here private: std::shared_ptr<Object> obj; }; If this header is included in a cpp file, (which we'll call "main.cpp"), this will result in a compilation error, because even though no destructor is specified, the destructor will still need to be generated by the compiler because std::shared_ptr's destructor is *not* trivial (in other words, it does something other than nothing), as std::shared_ptr's destructor needs to do two things: 1. Decrement the shared reference count of the object being pointed to, and if the reference count decrements to zero, 2. Free the Object instance's memory (aka deallocate the memory it's pointing to). And so the compiler generates the code for the destructor doing this inside main.cpp. Now, keep in mind, the Object forward declaration is not a complete type. All it does is tell the compiler "a type named Object exists" and allows us to use the name in certain situations to avoid a header dependency. So the compiler needs to generate destruction code for Object, but the compiler doesn't know *how* to destruct it. A forward declaration doesn't tell the compiler anything about Object's constructor or destructor. So, the compiler will issue an error in this case because it's undefined behavior to try and deallocate (or construct) an incomplete type and std::shared_ptr and std::unique_ptr make sure this isn't the case internally. Now, if we had defaulted the destructor in "thing.cpp", where we also include "object.h", this would never be an issue, as the destructor would only have its code generated in one place, and it would be in a place where the full class definition of Object would be visible to the compiler. ---------------------- End example ---------------------------- Given these service classes are more than certainly going to change in the future, this defaults the constructors and destructors into the relevant cpp files to make the construction and destruction of all of the services consistent and unlikely to run into cases where forward declarations are indirectly causing compilation errors. It also has the plus of avoiding the need to rebuild several services if destruction logic changes, since it would only be necessary to recompile the single cpp file.
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~BSDCFG() override;
};
} // namespace Service::Sockets