fix: add FreeBSD support for local address handling

- Add FreeBSD-specific packet info handling in ENet unix.c
- Use IP_RECVDSTADDR/IP_SENDSRCADDR for FreeBSD instead of IP_PKTINFO
- Enable IP_RECVDSTADDR socket option on video/audio sockets for FreeBSD
- Remove incorrect IP_PKTINFO macro redefinition from misc.cpp
- Add FreeBSD-specific send code in Sunshine's UDP streaming functions

Co-authored-by: ReenigneArcher <42013603+ReenigneArcher@users.noreply.github.com>

patches/enet_freebsd.patch

@@ -0,0 +1,63 @@
+diff --git a/unix.c b/unix.c
+index 1234567..abcdefg 100644
+--- a/unix.c
++++ b/unix.c
+@@ -373,6 +373,14 @@ enet_socket_create (ENetSocketType type, int af)
+     }
+ #endif
+ 
++#if defined(__FreeBSD__) && defined(IP_RECVDSTADDR)
++    {
++        // Enable IP_RECVDSTADDR for FreeBSD to receive destination address
++        int on = 1;
++        setsockopt(sock, IPPROTO_IP, IP_RECVDSTADDR, (char *)&on, sizeof(on));
++    }
++#endif
++
+ #ifdef IP_PKTINFO
+     {
+         // We turn this on for all sockets because it may be required for IPv4
+@@ -617,6 +625,21 @@ enet_socket_send (ENetSocket socket,
+     // from this peer to ensure it correctly recognizes our responses as
+     // coming from the expected host.
+     if (localAddress != NULL) {
++#if defined(__FreeBSD__) && defined(IP_SENDSRCADDR)
++        if (localAddress->address.ss_family == AF_INET) {
++            struct in_addr srcAddr = ((struct sockaddr_in*)&localAddress->address)->sin_addr;
++
++            msgHdr.msg_control = controlBufData;
++            msgHdr.msg_controllen = CMSG_SPACE(sizeof(srcAddr));
++
++            struct cmsghdr *chdr = CMSG_FIRSTHDR(&msgHdr);
++            chdr->cmsg_level = IPPROTO_IP;
++            chdr->cmsg_type = IP_SENDSRCADDR;
++            chdr->cmsg_len = CMSG_LEN(sizeof(srcAddr));
++            memcpy(CMSG_DATA(chdr), &srcAddr, sizeof(srcAddr));
++        }
++        else
++#endif
+ #ifdef IP_PKTINFO
+         if (localAddress->address.ss_family == AF_INET) {
+             struct in_pktinfo pktInfo;
+@@ -744,6 +767,21 @@ enet_socket_receive (ENetSocket socket,
+     // to ensure we respond from the correct address/interface.
+     if (localAddress != NULL) {
+         for (struct cmsghdr *chdr = CMSG_FIRSTHDR(&msgHdr); chdr != NULL; chdr = CMSG_NXTHDR(&msgHdr, chdr)) {
++#if defined(__FreeBSD__) && defined(IP_RECVDSTADDR)
++            if (chdr->cmsg_level == IPPROTO_IP && chdr->cmsg_type == IP_RECVDSTADDR) {
++                struct sockaddr_in *localAddr = (struct sockaddr_in*)&localAddress->address;
++
++                localAddr->sin_family = AF_INET;
++                localAddr->sin_addr = *(struct in_addr*)CMSG_DATA(chdr);
++                // FreeBSD doesn't populate sin_port in RECVDSTADDR, but we don't need it
++                // since we only use the address part for routing decisions
++                localAddr->sin_port = 0;
++
++                localAddress->addressLength = sizeof(*localAddr);
++                break;
++            }
++            else
++#endif
+ #ifdef IP_PKTINFO
+             if (chdr->cmsg_level == IPPROTO_IP && chdr->cmsg_type == IP_PKTINFO) {
+                 struct sockaddr_in *localAddr = (struct sockaddr_in*)&localAddress->address;

src/platform/linux/misc.cpp

@@ -39,9 +39,6 @@
   #include <netinet/in.h>
   #include <sys/socket.h>
   // Define constants that are missing in FreeBSD
-  #ifndef IP_PKTINFO  // packet info for IPv4
-    #define IP_PKTINFO IP_RECVDSTADDR
-  #endif
   #ifndef SOL_IP  // socket level for IPv4
     #define SOL_IP IPPROTO_IP
   #endif
@@ -51,12 +48,6 @@
   #ifndef SO_PRIORITY  // socket option for priority, disabled for FreeBSD
     #define SO_PRIORITY -1
   #endif
-// Define in_pktinfo structure for IPv4 packet info
-struct in_pktinfo {
-  struct in_addr ipi_addr;
-  struct in_addr ipi_spec_dst;
-  int ipi_ifindex;
-};
 #endif
 
 #ifdef __GNUC__
@@ -401,7 +392,11 @@ namespace platf {
     }
 
     union {
+#ifdef __FreeBSD__
+      char buf[CMSG_SPACE(sizeof(uint16_t)) + std::max(CMSG_SPACE(sizeof(struct in_addr)), CMSG_SPACE(sizeof(struct in6_pktinfo)))];
+#else
       char buf[CMSG_SPACE(sizeof(uint16_t)) + std::max(CMSG_SPACE(sizeof(struct in_pktinfo)), CMSG_SPACE(sizeof(struct in6_pktinfo)))];
+#endif
       struct cmsghdr alignment;
     } cmbuf = {};  // Must be zeroed for CMSG_NXTHDR()
 
@@ -427,6 +422,18 @@ namespace platf {
       pktinfo_cm->cmsg_len = CMSG_LEN(sizeof(pktInfo));
       memcpy(CMSG_DATA(pktinfo_cm), &pktInfo, sizeof(pktInfo));
     } else {
+#ifdef __FreeBSD__
+      // FreeBSD uses IP_SENDSRCADDR instead of IP_PKTINFO
+      struct sockaddr_in saddr_v4 = to_sockaddr(send_info.source_address.to_v4(), 0);
+      struct in_addr srcAddr = saddr_v4.sin_addr;
+
+      cmbuflen += CMSG_SPACE(sizeof(srcAddr));
+
+      pktinfo_cm->cmsg_level = IPPROTO_IP;
+      pktinfo_cm->cmsg_type = IP_SENDSRCADDR;
+      pktinfo_cm->cmsg_len = CMSG_LEN(sizeof(srcAddr));
+      memcpy(CMSG_DATA(pktinfo_cm), &srcAddr, sizeof(srcAddr));
+#else
       struct in_pktinfo pktInfo;
 
       struct sockaddr_in saddr_v4 = to_sockaddr(send_info.source_address.to_v4(), 0);
@@ -439,6 +446,7 @@ namespace platf {
       pktinfo_cm->cmsg_type = IP_PKTINFO;
       pktinfo_cm->cmsg_len = CMSG_LEN(sizeof(pktInfo));
       memcpy(CMSG_DATA(pktinfo_cm), &pktInfo, sizeof(pktInfo));
+#endif
     }
 
     auto const max_iovs_per_msg = send_info.payload_buffers.size() + (send_info.headers ? 1 : 0);
@@ -608,7 +616,11 @@ namespace platf {
     }
 
     union {
+#ifdef __FreeBSD__
+      char buf[std::max(CMSG_SPACE(sizeof(struct in_addr)), CMSG_SPACE(sizeof(struct in6_pktinfo)))];
+#else
       char buf[std::max(CMSG_SPACE(sizeof(struct in_pktinfo)), CMSG_SPACE(sizeof(struct in6_pktinfo)))];
+#endif
       struct cmsghdr alignment;
     } cmbuf;
 
@@ -632,6 +644,18 @@ namespace platf {
       pktinfo_cm->cmsg_len = CMSG_LEN(sizeof(pktInfo));
       memcpy(CMSG_DATA(pktinfo_cm), &pktInfo, sizeof(pktInfo));
     } else {
+#ifdef __FreeBSD__
+      // FreeBSD uses IP_SENDSRCADDR instead of IP_PKTINFO
+      struct sockaddr_in saddr_v4 = to_sockaddr(send_info.source_address.to_v4(), 0);
+      struct in_addr srcAddr = saddr_v4.sin_addr;
+
+      cmbuflen += CMSG_SPACE(sizeof(srcAddr));
+
+      pktinfo_cm->cmsg_level = IPPROTO_IP;
+      pktinfo_cm->cmsg_type = IP_SENDSRCADDR;
+      pktinfo_cm->cmsg_len = CMSG_LEN(sizeof(srcAddr));
+      memcpy(CMSG_DATA(pktinfo_cm), &srcAddr, sizeof(srcAddr));
+#else
       struct in_pktinfo pktInfo;
 
       struct sockaddr_in saddr_v4 = to_sockaddr(send_info.source_address.to_v4(), 0);
@@ -644,6 +668,7 @@ namespace platf {
       pktinfo_cm->cmsg_type = IP_PKTINFO;
       pktinfo_cm->cmsg_len = CMSG_LEN(sizeof(pktInfo));
       memcpy(CMSG_DATA(pktinfo_cm), &pktInfo, sizeof(pktInfo));
+#endif
     }
 
     struct iovec iovs[2];

src/stream.cpp

@@ -8,6 +8,11 @@
 #include <future>
 #include <queue>
 
+#ifdef __FreeBSD__
+  #include <netinet/in.h>
+  #include <sys/socket.h>
+#endif
+
 // lib includes
 #include <boost/endian/arithmetic.hpp>
 #include <openssl/err.h>
@@ -519,21 +524,11 @@ namespace stream {
       // Use the local address from the control connection as the source address
       // for other communications to the client. This is necessary to ensure
       // proper routing on multi-homed hosts.
-
-      // TODO: delete this debug log
-      BOOST_LOG(debug) << "Raw localAddress.address: family=" << peer->localAddress.address.ss_family
-                       << " size=" << peer->localAddress.addressLength
-                       << " data=" << util::hex_vec(std::string_view {(char *) &peer->localAddress.address, static_cast<long long unsigned int>(peer->localAddress.addressLength)});
       auto local_address = platf::from_sockaddr((sockaddr *) &peer->localAddress.address);
       if (local_address.empty()) {
         BOOST_LOG(warning) << "Couldn't get local address for control connection"sv;
       }
-      try {
-        session_p->localAddress = boost::asio::ip::make_address(local_address);
-      } catch (const boost::system::system_error &e) {
-        BOOST_LOG(error) << "boost::system::system_error in address parsing: " << e.what() << " (code: " << e.code() << ")"sv;
-        throw;
-      }
+      session_p->localAddress = boost::asio::ip::make_address(local_address);
 
       BOOST_LOG(debug) << "Control local address ["sv << local_address << ']';
       BOOST_LOG(debug) << "Control peer address ["sv << peer_addr << ':' << peer_port << ']';
@@ -1722,6 +1717,23 @@ namespace stream {
       return -1;
     }
 
+#ifdef __FreeBSD__
+    // Enable IP_RECVDSTADDR for FreeBSD to receive destination address for IPv4
+    {
+      int on = 1;
+      if (setsockopt(ctx.video_sock.native_handle(), IPPROTO_IP, IP_RECVDSTADDR, &on, sizeof(on)) < 0) {
+        BOOST_LOG(warning) << "Failed to set IP_RECVDSTADDR on video socket";
+      }
+    }
+    // Enable IPV6_RECVPKTINFO for IPv6
+    if (address_family == net::af_e::BOTH) {
+      int on = 1;
+      if (setsockopt(ctx.video_sock.native_handle(), IPPROTO_IPV6, IPV6_RECVPKTINFO, &on, sizeof(on)) < 0) {
+        BOOST_LOG(warning) << "Failed to set IPV6_RECVPKTINFO on video socket";
+      }
+    }
+#endif
+
     // Set video socket send buffer size (SO_SENDBUF) to 1MB
     try {
       ctx.video_sock.set_option(boost::asio::socket_base::send_buffer_size(1024 * 1024));
@@ -1743,6 +1755,23 @@ namespace stream {
       return -1;
     }
 
+#ifdef __FreeBSD__
+    // Enable IP_RECVDSTADDR for FreeBSD to receive destination address for IPv4
+    {
+      int on = 1;
+      if (setsockopt(ctx.audio_sock.native_handle(), IPPROTO_IP, IP_RECVDSTADDR, &on, sizeof(on)) < 0) {
+        BOOST_LOG(warning) << "Failed to set IP_RECVDSTADDR on audio socket";
+      }
+    }
+    // Enable IPV6_RECVPKTINFO for IPv6
+    if (address_family == net::af_e::BOTH) {
+      int on = 1;
+      if (setsockopt(ctx.audio_sock.native_handle(), IPPROTO_IPV6, IPV6_RECVPKTINFO, &on, sizeof(on)) < 0) {
+        BOOST_LOG(warning) << "Failed to set IPV6_RECVPKTINFO on audio socket";
+      }
+    }
+#endif
+
     ctx.audio_sock.bind(udp::endpoint(protocol, audio_port), ec);
     if (ec) {
       BOOST_LOG(fatal) << "Couldn't bind Audio server to port ["sv << audio_port << "]: "sv << ec.message();