[FFmpeg-devel] [PATCH v2] avformat: enable UDP IPv6 multicast interface selection using zone index
Ignjatović, Lazar (RS)
Lazar.Ignjatovic at cubic.com
Wed Mar 27 17:38:11 EET 2024
avformat: enable UDP IPv6 multicast interface selection using zone index
Enabled IPv6 interface selection using zone index. Properly resolved
interface index in places where default 0 interface index is used
(marked with TODO: within udp.c). Adjusted binding for multicast sockets
that are used for reading from the network.
For mcast addresses, bind to mcast address is attempted as before.
In case that this fails, which will happen on Windows, socket is bound
to INADDR_ANY/IN6ADDR_ANY_INIT depending on address family. Actual
interface selection is performed using udp_set_multicast_interface to
point to the desired interface for sending.
Closes: #368
Signed-off-by: Lazar Ignjatovic <Lazar.Ignjatovic at cubic.com>
---
V1 -> V2 reverted iface resolution for IPv4 MCAST_JOIN_SOURCE_GROUP
NOTE: Due to comments, this patch is proposed as one of two alternatives
The other alternative uses `localaddr` for defining interfaces.
configure | 3 ++
doc/protocols.texi | 2 +-
libavformat/network.h | 6 +++
libavformat/udp.c | 85 +++++++++++++++++++++++++++++++++++++++----
4 files changed, 88 insertions(+), 8 deletions(-)
diff --git a/configure b/configure
index 2a1d22310b..35d6a0b78c 100755
--- a/configure
+++ b/configure
@@ -2307,6 +2307,7 @@ HEADERS_LIST="
valgrind_valgrind_h
windows_h
winsock2_h
+ iphlpapi_h
"
INTRINSICS_LIST="
@@ -6475,6 +6476,8 @@ if ! disabled network; then
check_struct winsock2.h "struct sockaddr" sa_len
check_type ws2tcpip.h "struct sockaddr_in6"
check_type ws2tcpip.h "struct sockaddr_storage"
+ check_headers iphlpapi.h -liphlpapi && network_extralibs="$network_extralibs -liphlpapi" || disable iphlpapi_h
+ check_func_headers iphlpapi.h GetBestInterfaceEx $network_extralibs
else
disable network
fi
diff --git a/doc/protocols.texi b/doc/protocols.texi
index f54600b846..a8892845d3 100644
--- a/doc/protocols.texi
+++ b/doc/protocols.texi
@@ -2027,7 +2027,7 @@ packet bursts.
Override the local UDP port to bind with.
@item localaddr=@var{addr}
-Local IP address of a network interface used for sending packets or joining
+Local IPv4 address of a network interface used for sending packets or joining
multicast groups.
@item pkt_size=@var{size}
diff --git a/libavformat/network.h b/libavformat/network.h
index ca214087fc..2461b651d4 100644
--- a/libavformat/network.h
+++ b/libavformat/network.h
@@ -38,6 +38,10 @@
#include <winsock2.h>
#include <ws2tcpip.h>
+#if HAVE_IPHLPAPI_H
+#include <iphlpapi.h>
+#endif
+
#ifndef EPROTONOSUPPORT
#define EPROTONOSUPPORT WSAEPROTONOSUPPORT
#endif
@@ -64,6 +68,8 @@ int ff_neterrno(void);
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <netdb.h>
+#include <net/if.h>
+#include <ifaddrs.h>
#define ff_neterrno() AVERROR(errno)
#endif /* HAVE_WINSOCK2_H */
diff --git a/libavformat/udp.c b/libavformat/udp.c
index d9514f5026..00c73f9ec9 100644
--- a/libavformat/udp.c
+++ b/libavformat/udp.c
@@ -35,6 +35,7 @@
#include "libavutil/opt.h"
#include "libavutil/log.h"
#include "libavutil/time.h"
+#include "libavutil/avstring.h"
#include "internal.h"
#include "network.h"
#include "os_support.h"
@@ -220,8 +221,7 @@ static int udp_join_multicast_group(int sockfd, struct sockaddr *addr,
struct ipv6_mreq mreq6;
memcpy(&mreq6.ipv6mr_multiaddr, &(((struct sockaddr_in6 *)addr)->sin6_addr), sizeof(struct in6_addr));
- //TODO: Interface index should be looked up from local_addr
- mreq6.ipv6mr_interface = 0;
+ mreq6.ipv6mr_interface = ((struct sockaddr_in6 *)addr)->sin6_scope_id;
if (setsockopt(sockfd, IPPROTO_IPV6, IPV6_ADD_MEMBERSHIP, &mreq6, sizeof(mreq6)) < 0) {
ff_log_net_error(logctx, AV_LOG_ERROR, "setsockopt(IPV6_ADD_MEMBERSHIP)");
return ff_neterrno();
@@ -231,6 +231,39 @@ static int udp_join_multicast_group(int sockfd, struct sockaddr *addr,
return 0;
}
+static int udp_set_multicast_interface(int sockfd, struct sockaddr *addr,
+ struct sockaddr *local_addr, void *logctx)
+{
+#ifdef IP_MULTICAST_IF
+ if (addr->sa_family == AF_INET) {
+ struct ip_mreq mreq;
+
+ mreq.imr_multiaddr.s_addr = ((struct sockaddr_in *)addr)->sin_addr.s_addr;
+ if (local_addr)
+ mreq.imr_interface = ((struct sockaddr_in *)local_addr)->sin_addr;
+ else
+ mreq.imr_interface.s_addr = INADDR_ANY;
+
+ if (setsockopt(sockfd, IPPROTO_IP, IP_MULTICAST_IF, (const void *)&mreq, sizeof(mreq)) < 0) {
+ ff_log_net_error(logctx, AV_LOG_ERROR, "setsockopt(IP_MULTICAST_IF)");
+ return ff_neterrno();
+ }
+ }
+#endif
+#if defined(IPV6_MULTICAST_IF) && defined(IPPROTO_IPV6)
+ if (addr->sa_family == AF_INET6) {
+ unsigned int iface;
+ iface = ((struct sockaddr_in6 *)addr)->sin6_scope_id;
+
+ if (setsockopt(sockfd, IPPROTO_IPV6, IPV6_MULTICAST_IF, &iface, sizeof(unsigned int)) < 0) {
+ ff_log_net_error(logctx, AV_LOG_ERROR, "setsockopt(IPV6_MULTICAST_IF)");
+ return ff_neterrno();
+ }
+ }
+#endif
+ return 0;
+}
+
static int udp_leave_multicast_group(int sockfd, struct sockaddr *addr,
struct sockaddr *local_addr, void *logctx)
{
@@ -254,8 +287,7 @@ static int udp_leave_multicast_group(int sockfd, struct sockaddr *addr,
struct ipv6_mreq mreq6;
memcpy(&mreq6.ipv6mr_multiaddr, &(((struct sockaddr_in6 *)addr)->sin6_addr), sizeof(struct in6_addr));
- //TODO: Interface index should be looked up from local_addr
- mreq6.ipv6mr_interface = 0;
+ mreq6.ipv6mr_interface = ((struct sockaddr_in6 *)addr)->sin6_scope_id;
if (setsockopt(sockfd, IPPROTO_IPV6, IPV6_DROP_MEMBERSHIP, &mreq6, sizeof(mreq6)) < 0) {
ff_log_net_error(logctx, AV_LOG_ERROR, "setsockopt(IPV6_DROP_MEMBERSHIP)");
return -1;
@@ -284,6 +316,9 @@ static int udp_set_multicast_sources(URLContext *h,
//TODO: Interface index should be looked up from local_addr
mreqs.gsr_interface = 0;
+ if (level == IPPROTO_IPV6)
+ mreqs.gsr_interface = ((struct sockaddr_in6 *)addr)->sin6_scope_id;
+
memcpy(&mreqs.gsr_group, addr, addr_len);
memcpy(&mreqs.gsr_source, &sources[i], sizeof(*sources));
@@ -340,9 +375,24 @@ static int udp_set_url(URLContext *h,
{
struct addrinfo *res0;
int addr_len;
+ const char *host, *sc;
+ char address[1024], scope[1024];
- res0 = ff_ip_resolve_host(h, hostname, port, SOCK_DGRAM, AF_UNSPEC, 0);
+ if (sc = strchr(hostname, '%')) {
+ av_strlcpy(address, hostname, FFMIN(1024, sc - hostname + 1));
+ av_strlcpy(scope, sc + 1, FFMIN(1024, strlen(hostname) - (sc - hostname)));
+ host = address;
+ } else {
+ host = hostname;
+ }
+
+ res0 = ff_ip_resolve_host(h, host, port, SOCK_DGRAM, AF_UNSPEC, 0);
if (!res0) return AVERROR(EIO);
+#if HAVE_IPHLPAPI_H || !HAVE_WINSOCK2_H
+ if (res0->ai_family== AF_INET6 && strlen(scope) > 0) {
+ ((struct sockaddr_in6*)res0->ai_addr)->sin6_scope_id = if_nametoindex(scope);
+ }
+#endif
memcpy(addr, res0->ai_addr, res0->ai_addrlen);
addr_len = res0->ai_addrlen;
freeaddrinfo(res0);
@@ -841,8 +891,23 @@ static int udp_open(URLContext *h, const char *uri, int flags)
if (s->is_multicast && (h->flags & AVIO_FLAG_READ)) {
bind_ret = bind(udp_fd,(struct sockaddr *)&s->dest_addr, len);
}
- /* bind to the local address if not multicast or if the multicast
- * bind failed */
+
+ /* bind to ADDR_ANY if the multicast bind failed */
+ if (s->is_multicast && bind_ret < 0) {
+ struct addrinfo *res;
+
+ if (s->dest_addr.ss_family == AF_INET)
+ res = ff_ip_resolve_host(h, "0.0.0.0", 0, SOCK_DGRAM, AF_UNSPEC, 0);
+ else if (s->dest_addr.ss_family == AF_INET6)
+ res = ff_ip_resolve_host(h, "::", 0, SOCK_DGRAM, AF_UNSPEC, 0);
+
+ if (res && res->ai_addr) {
+ bind_ret = bind(udp_fd, res->ai_addr, res->ai_addrlen);
+ }
+
+ freeaddrinfo(res);
+ }
+
/* the bind is needed to give a port to the socket now */
if (bind_ret < 0 && bind(udp_fd,(struct sockaddr *)&my_addr, len) < 0) {
ff_log_net_error(h, AV_LOG_ERROR, "bind failed");
@@ -855,6 +920,12 @@ static int udp_open(URLContext *h, const char *uri, int flags)
s->local_port = udp_port(&my_addr, len);
if (s->is_multicast) {
+ if ((ret = udp_set_multicast_interface(udp_fd,
+ (struct sockaddr *)&s->dest_addr,
+ (struct sockaddr *)&s->local_addr_storage,
+ h)) < 0)
+ goto fail;
+
if (h->flags & AVIO_FLAG_WRITE) {
/* output */
if ((ret = udp_set_multicast_ttl(udp_fd, s->ttl, (struct sockaddr *)&s->dest_addr, h)) < 0)
--
2.41.0.windows.2
This message has been marked as Public on 03/27/2024 15:38Z.
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