From 974ed0166cec62721c8acc462c1aaf21d1909d97 Mon Sep 17 00:00:00 2001
From: Max Kellermann <mk@cm4all.com>
Date: Fri, 12 Jan 2024 11:55:25 +0100
Subject: [PATCH] net/SocketDescriptor: add sendmsg(), recvmsg() wrappers

---
 src/net/SocketDescriptor.cxx | 16 ++++++++++++++++
 src/net/SocketDescriptor.hxx | 14 ++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/src/net/SocketDescriptor.cxx b/src/net/SocketDescriptor.cxx
index 8cdce6f6e..b86a07dfa 100644
--- a/src/net/SocketDescriptor.cxx
+++ b/src/net/SocketDescriptor.cxx
@@ -417,6 +417,12 @@ SocketDescriptor::Receive(std::span<std::byte> dest, int flags) const noexcept
 	return ::recv(Get(), (char *)dest.data(), dest.size(), flags);
 }
 
+ssize_t
+SocketDescriptor::Receive(struct msghdr &msg, int flags) const noexcept
+{
+	return ::recvmsg(Get(), &msg, flags);
+}
+
 ssize_t
 SocketDescriptor::Send(std::span<const std::byte> src, int flags) const noexcept
 {
@@ -427,6 +433,16 @@ SocketDescriptor::Send(std::span<const std::byte> src, int flags) const noexcept
 	return ::send(Get(), (const char *)src.data(), src.size(), flags);
 }
 
+ssize_t
+SocketDescriptor::Send(const struct msghdr &msg, int flags) const noexcept
+{
+#ifdef __linux__
+	flags |= MSG_NOSIGNAL;
+#endif
+
+	return ::sendmsg(Get(), &msg, flags);
+}
+
 ssize_t
 SocketDescriptor::ReadNoWait(std::span<std::byte> dest) const noexcept
 {
diff --git a/src/net/SocketDescriptor.hxx b/src/net/SocketDescriptor.hxx
index 03a994bb0..029c4ed83 100644
--- a/src/net/SocketDescriptor.hxx
+++ b/src/net/SocketDescriptor.hxx
@@ -303,6 +303,12 @@ public:
 	[[nodiscard]]
 	ssize_t Receive(std::span<std::byte> dest, int flags=0) const noexcept;
 
+	/**
+	 * Wrapper for recvmsg().
+	 */
+	[[nodiscard]]
+	ssize_t Receive(struct msghdr &msg, int flags=0) const noexcept;
+
 	/**
 	 * Wrapper for send().
 	 *
@@ -311,6 +317,14 @@ public:
 	[[nodiscard]]
 	ssize_t Send(std::span<const std::byte> src, int flags=0) const noexcept;
 
+	/**
+	 * Wrapper for sendmsg().
+	 *
+	 * MSG_NOSIGNAL is implicitly added (if available).
+	 */
+	[[nodiscard]]
+	ssize_t Send(const struct msghdr &msg, int flags=0) const noexcept;
+
 	[[nodiscard]]
 	ssize_t Read(std::span<std::byte> dest) const noexcept {
 		return Receive(dest);