From 7b712844e38bdfc1ef728e257fb8616c16ec4cc8 Mon Sep 17 00:00:00 2001 From: Jo-Philipp Wich Date: Thu, 19 Nov 2015 21:43:10 +0100 Subject: properly handle point-to-point interfaces in getifaddrs() With point-to-point interfaces, the IFA_ADDRESS netlink attribute contains the peer address while an extra attribute IFA_LOCAL carries the actual local interface address. Both the glibc and uclibc implementations of getifaddrs() handle this case by moving the ifa_addr contents to the broadcast/remote address union and overwriting ifa_addr upon receipt of an IFA_LOCAL attribute. This patch adds the same special treatment logic of IFA_LOCAL to musl's implementation of getifaddrs() in order to align its behaviour with that of uclibc and glibc. Signed-off-by: Jo-Philipp Wich --- src/network/getifaddrs.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) (limited to 'src/network/getifaddrs.c') diff --git a/src/network/getifaddrs.c b/src/network/getifaddrs.c index 89a8f729..fed75bd8 100644 --- a/src/network/getifaddrs.c +++ b/src/network/getifaddrs.c @@ -162,13 +162,26 @@ static int netlink_msg_to_ifaddr(void *pctx, struct nlmsghdr *h) for (rta = NLMSG_RTA(h, sizeof(*ifa)); NLMSG_RTAOK(rta, h); rta = RTA_NEXT(rta)) { switch (rta->rta_type) { case IFA_ADDRESS: - copy_addr(&ifs->ifa.ifa_addr, ifa->ifa_family, &ifs->addr, RTA_DATA(rta), RTA_DATALEN(rta), ifa->ifa_index); + /* If ifa_addr is already set we, received an IFA_LOCAL before + * so treat this as destination address */ + if (ifs->ifa.ifa_addr) + copy_addr(&ifs->ifa.ifa_dstaddr, ifa->ifa_family, &ifs->ifu, RTA_DATA(rta), RTA_DATALEN(rta), ifa->ifa_index); + else + copy_addr(&ifs->ifa.ifa_addr, ifa->ifa_family, &ifs->addr, RTA_DATA(rta), RTA_DATALEN(rta), ifa->ifa_index); break; case IFA_BROADCAST: - /* For point-to-point links this is peer, but ifa_broadaddr - * and ifa_dstaddr are union, so this works for both. */ copy_addr(&ifs->ifa.ifa_broadaddr, ifa->ifa_family, &ifs->ifu, RTA_DATA(rta), RTA_DATALEN(rta), ifa->ifa_index); break; + case IFA_LOCAL: + /* If ifa_addr is set and we get IFA_LOCAL, assume we have + * a point-to-point network. Move address to correct field. */ + if (ifs->ifa.ifa_addr) { + ifs->ifu = ifs->addr; + ifs->ifa.ifa_dstaddr = &ifs->ifu.sa; + memset(&ifs->addr, 0, sizeof(ifs->addr)); + } + copy_addr(&ifs->ifa.ifa_addr, ifa->ifa_family, &ifs->addr, RTA_DATA(rta), RTA_DATALEN(rta), ifa->ifa_index); + break; case IFA_LABEL: if (RTA_DATALEN(rta) < sizeof(ifs->name)) { memcpy(ifs->name, RTA_DATA(rta), RTA_DATALEN(rta)); -- cgit v1.2.1