diff --git a/src/udprelay.c b/src/udprelay.c index 816b35a7..98763b82 100644 --- a/src/udprelay.c +++ b/src/udprelay.c @@ -313,26 +313,59 @@ int create_remote_socket(int ipv6) int create_server_socket(const char *host, const char *port) { struct addrinfo hints; - struct addrinfo *result, *rp; + struct addrinfo *result, *rp, *ipv4v6bindall; int s, server_sock; memset(&hints, 0, sizeof(struct addrinfo)); hints.ai_family = AF_UNSPEC; /* Return IPv4 and IPv6 choices */ hints.ai_socktype = SOCK_DGRAM; /* We want a UDP socket */ - + hints.ai_flags = AI_ALL | AI_V4MAPPED | AI_PASSIVE | AI_ADDRCONFIG; /* For wildcard IP address */ + hints.ai_protocol = IPPROTO_UDP; + s = getaddrinfo(host, port, &hints, &result); if (s != 0) { LOGE("[udp] getaddrinfo: %s", gai_strerror(s)); return -1; } - for (rp = result; rp != NULL; rp = rp->ai_next) { + rp = result; + + /* + On Linux, with net.ipv6.bindv6only = 0 (the default), getaddrinfo(NULL) with + AI_PASSIVE returns 0.0.0.0 and :: (in this order). AI_PASSIVE was meant to + return a list of addresses to listen on, but it is impossible to listen on + 0.0.0.0 and :: at the same time, if :: implies dualstack mode. + */ + if (!host) { + ipv4v6bindall = result; + + /* Loop over all address infos found until a IPV6 address is found. */ + while (ipv4v6bindall) { + if (ipv4v6bindall->ai_family == AF_INET6) { + rp = ipv4v6bindall; /* Take first IPV6 address available */ + break; + } + + ipv4v6bindall = ipv4v6bindall->ai_next; /* Get next address info, if any */ + } + } + + for (/*rp = result*/; rp != NULL; rp = rp->ai_next) { server_sock = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol); if (server_sock == -1) { continue; } int opt = 1; + + if (rp->ai_family == AF_INET6) { + int ipv6only = 0; + if (host) { + ipv6only = 1; + } + setsockopt(server_sock, IPPROTO_IPV6, IPV6_V6ONLY, &ipv6only, sizeof(ipv6only)); + } + setsockopt(server_sock, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)); #ifdef SO_NOSIGPIPE set_nosigpipe(server_sock);