openggsn: Check return codes and take error paths on failure. Return early when socket() returns -1, and check return codes where indicated by some TODOs. This removes 2 TODOs and fixes a compiler warning about assignment to a variable which then isn't used. Signed-off-by: Michael McTernan &lt;mike.mcternan(a)wavemobile.com&gt; Index: osmobss/openggsn/lib/tun.c =================================================================== --- osmobss.orig/openggsn/lib/tun.c 2015-04-28 10:51:37.960449539 +0100 +++ osmobss/openggsn/lib/tun.c 2015-04-28 10:54:40.301130739 +0100 @@ -117,6 +117,7 @@ int tun_sifflags(struct tun_t *this, int ifr.ifr_name[IFNAMSIZ - 1] = 0; /* Make sure to terminate */ if ((fd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { SYS_ERR(DTUN, LOGL_ERROR, errno, "socket() failed"); + return -1; } if (ioctl(fd, SIOCSIFFLAGS, &ifr)) { SYS_ERR(DTUN, LOGL_ERROR, errno, @@ -318,9 +319,19 @@ int tun_addaddr(struct tun_t *this, req.n.nlmsg_seq = 0; req.n.nlmsg_flags |= NLM_F_ACK; - status = sendmsg(fd, &msg, 0); /* TODO Error check */ + status = sendmsg(fd, &msg, 0); + if (status == -1) { + SYS_ERR(DTUN, LOGL_ERROR, errno, "sendmsg() failed"); + close(fd); + return -1; + } + + status = tun_sifflags(this, IFF_UP | IFF_RUNNING); + if (status == -1) { + close(fd); + return -1; + } - tun_sifflags(this, IFF_UP | IFF_RUNNING); /* TODO */ close(fd); this->addrs++; return 0;