[FFmpeg-devel] [PATCH] Fix setsockopt IP_MULTICAST_TTL on OpenBSD

[Brad Smith]

On Mon, Jan 24, 2022 at 01:40:47PM +0100, Michael Niedermayer wrote:
> On Sun, Jan 23, 2022 at 02:55:38PM -0500, Brad Smith wrote:
> > On 1/23/2022 6:57 AM, Michael Niedermayer wrote:
> > 
> > > On Wed, Jan 12, 2022 at 12:13:13AM -0500, Brad Smith wrote:
> > > > Fix setsockopt() usage on OpenBSD with IP_MULTICAST_TTL. The field
> > > > type should be an unsigned char on anything but Linux.
> > > > 
> > > > 
> > > > diff --git a/libavformat/udp.c b/libavformat/udp.c
> > > > index 180d96a988..29aa865fff 100644
> > > > --- a/libavformat/udp.c
> > > > +++ b/libavformat/udp.c
> > > > @@ -163,7 +163,13 @@ static int udp_set_multicast_ttl(int sockfd, int mcastTTL,
> > > >   {
> > > >   #ifdef IP_MULTICAST_TTL
> > > >       if (addr->sa_family == AF_INET) {
> > > > -        if (setsockopt(sockfd, IPPROTO_IP, IP_MULTICAST_TTL, &mcastTTL, sizeof(mcastTTL)) < 0) {
> > > > +#ifdef __linux__
> > > > +        int ttl = mcastTTL;
> > > > +#else
> > > > +        unsigned char ttl = mcastTTL;
> > > > +#endif
> > > this "ifdef __linux__" feels like the wrong thing to check, dont you agree ?
> > 
> > Not sure what you mean.
> 
> "__linux__" seems the wrong property to check for
> this is not
> #ifdef __linux__
> osname = "linux"
> #else
> 
> i would have expected more something like
> #if HAVE_INT_TTL
> int ttl = mcastTTL;
> #else
> 
> or maybe even something along the lines of
> 
> WHATEVER_TTL_TYPE ttl = mcastTTL;
> 
> thx

Ok, how about something like this?


diff --git a/configure b/configure
index 493493b4c5..055ff3c206 100755
--- a/configure
+++ b/configure
@@ -3838,6 +3838,8 @@ doc_deps_any="manpages htmlpages podpages txtpages"
 
 logfile="ffbuild/config.log"
 
+multicast_ttl_type='unsigned char'
+
 # installation paths
 prefix_default="/usr/local"
 bindir_default='${prefix}/bin'
@@ -5653,6 +5655,7 @@ case $target_os in
     linux)
         enable section_data_rel_ro
         enabled_any arm aarch64 && enable_weak linux_perf
+        multicast_ttl_type='int'
         ;;
     irix*)
         target_os=irix
@@ -7784,6 +7787,7 @@ cat > $TMPH <<EOF
 #define SLIBSUF "$SLIBSUF"
 #define HAVE_MMX2 HAVE_MMXEXT
 #define SWS_MAX_FILTER_SIZE $sws_max_filter_size
+#define MULTICAST_TTL_TYPE $multicast_ttl_type
 EOF
 
 test -n "$assert_level" &&
diff --git a/libavformat/udp.c b/libavformat/udp.c
index 83c042d079..179e719286 100644
--- a/libavformat/udp.c
+++ b/libavformat/udp.c
@@ -27,6 +27,8 @@
 #define _DEFAULT_SOURCE
 #define _BSD_SOURCE     /* Needed for using struct ip_mreq with recent glibc */
 
+#include "config.h"
+
 #include "avformat.h"
 #include "avio_internal.h"
 #include "libavutil/avassert.h"
@@ -164,7 +166,9 @@ static int udp_set_multicast_ttl(int sockfd, int mcastTTL,
 {
 #ifdef IP_MULTICAST_TTL
     if (addr->sa_family == AF_INET) {
-        if (setsockopt(sockfd, IPPROTO_IP, IP_MULTICAST_TTL, &mcastTTL, sizeof(mcastTTL)) < 0) {
+        MULTICAST_TTL_TYPE ttl = mcastTTL;
+
+        if (setsockopt(sockfd, IPPROTO_IP, IP_MULTICAST_TTL, &ttl, sizeof(ttl)) < 0) {
             ff_log_net_error(logctx, AV_LOG_ERROR, "setsockopt(IP_MULTICAST_TTL)");
             return ff_neterrno();
         }