[FFmpeg-devel] [PATCH v2 1/3] avformat/udp: use one setsockopt for ipv4/ipv6

[Marton Balint]

On Sat, 5 Feb 2022, lance.lmwang at gmail.com wrote:

> From: Limin Wang <lance.lmwang at gmail.com>
>
> Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
> ---
> libavformat/udp.c | 31 ++++++++++++++++++++-----------
> 1 file changed, 20 insertions(+), 11 deletions(-)
>
> diff --git a/libavformat/udp.c b/libavformat/udp.c
> index 83c042d..3dc79eb 100644
> --- a/libavformat/udp.c
> +++ b/libavformat/udp.c
> @@ -162,22 +162,31 @@ static int udp_set_multicast_ttl(int sockfd, int mcastTTL,
>                                  struct sockaddr *addr,
>                                  void *logctx)
> {
> +    int protocol, cmd;
> +
> +    switch (addr->sa_family) {
> #ifdef IP_MULTICAST_TTL
> -    if (addr->sa_family == AF_INET) {
> -        if (setsockopt(sockfd, IPPROTO_IP, IP_MULTICAST_TTL, &mcastTTL, sizeof(mcastTTL)) < 0) {
> -            ff_log_net_error(logctx, AV_LOG_ERROR, "setsockopt(IP_MULTICAST_TTL)");
> -            return ff_neterrno();
> -        }
> -    }
> +        case AF_INET:
> +            protocol = IPPROTO_IP;
> +            cmd      = IP_MULTICAST_TTL;
> +            break;
> #endif
> #if defined(IPPROTO_IPV6) && defined(IPV6_MULTICAST_HOPS)
> -    if (addr->sa_family == AF_INET6) {
> -        if (setsockopt(sockfd, IPPROTO_IPV6, IPV6_MULTICAST_HOPS, &mcastTTL, sizeof(mcastTTL)) < 0) {
> -            ff_log_net_error(logctx, AV_LOG_ERROR, "setsockopt(IPV6_MULTICAST_HOPS)");
> +        case AF_INET6:
> +            protocol = IPPROTO_IPV6;
> +            cmd      = IPV6_MULTICAST_HOPS;
> +            break;
> +#endif
> +        default:
> +            errno = EAFNOSUPPORT;

This is not portable, ff_neterrno is different for winsock. Maybe you 
should simply remove the default case, to make it work like the old code, 
and not mix behaviour changes with factorization.

>             return ff_neterrno();
> -        }
>     }
> -#endif
> +
> +    if (setsockopt(sockfd, protocol, cmd, &mcastTTL, sizeof(mcastTTL)) < 0) {
> +        ff_log_net_error(logctx, AV_LOG_ERROR, "setsockopt");

"setsockopt(IPV4/IPV6 MULTICAST TTL)", so we know that the issue was with 
TTL setting?

Thanks,
Marton