Linux: Fix detecting existing IPv4 addresses

This is important for better NetworkManager support.

diff --git a/src/if-linux.c b/src/if-linux.c
index 0cda9e780e25f95f017eabb8b59abb95e31ec525..f09cda6ac41854734656549782d46117b9614cca 100644 (file)
--- a/src/if-linux.c
+++ b/src/if-linux.c
@@ -743,6 +743,7 @@ link_addr(struct dhcpcd_ctx *ctx, struct interface *ifp, struct nlmsghdr *nlm)
        struct priv *priv;
 #ifdef INET
        struct in_addr addr, net, brd;
+       int ret;
 #endif
 #ifdef INET6
        struct in6_addr addr6;
@@ -805,7 +806,11 @@ link_addr(struct dhcpcd_ctx *ctx, struct interface *ifp, struct nlmsghdr *nlm)
 
                /* Validate RTM_DELADDR really means address deleted
                 * and anything else really means address exists. */
-               if (if_addressexists(ifp, &addr) == 1) {
+               ret = if_addressexists(ifp, &addr);
+               if (ret == -1) {
+                       logerr("if_addressexists: %s", inet_ntoa(addr));
+                       break;
+               } else if (ret == 1) {
                        if (nlm->nlmsg_type == RTM_DELADDR)
                                break;
                } else {
@@ -1080,11 +1085,8 @@ if_sendnetlink(struct dhcpcd_ctx *ctx, int protocol, struct nlmsghdr *hdr,
 
        switch (protocol) {
        case NETLINK_ROUTE:
-               if (hdr->nlmsg_type != RTM_GETADDR) {
-                       s = priv->route_fd;
-                       break;
-               }
-               /* FALLTHROUGH */
+               s = priv->route_fd;
+               break;
        case NETLINK_GENERIC:
                s = priv->generic_fd;
 #if 0
@@ -1442,6 +1444,7 @@ struct ifiaddr
 {
        unsigned int ifa_ifindex;
        struct in_addr ifa_addr;
+       bool ifa_found;
 };
 
 static int
@@ -1457,13 +1460,18 @@ _if_addressexists(__unused struct dhcpcd_ctx *ctx,
        ifa = NLMSG_DATA(nlm);
        if (ifa->ifa_index != ia->ifa_ifindex || ifa->ifa_family != AF_INET)
                return 0;
+
        rta = IFA_RTA(ifa);
        len = NLMSG_PAYLOAD(nlm, sizeof(*ifa));
        for (; RTA_OK(rta, len); rta = RTA_NEXT(rta, len)) {
                switch (rta->rta_type) {
                case IFA_LOCAL:
                        memcpy(&this_addr, RTA_DATA(rta), sizeof(this_addr));
-                       return this_addr == ia->ifa_addr.s_addr ? 1 : 0;
+                       if (this_addr == ia->ifa_addr.s_addr) {
+                               ia->ifa_found = true;
+                               return 1;
+                       }
+                       break;
                }
        }
        return 0;
@@ -1475,17 +1483,21 @@ if_addressexists(struct interface *ifp, struct in_addr *addr)
        struct ifiaddr ia = {
                .ifa_ifindex = ifp->index,
                .ifa_addr = *addr,
+               .ifa_found = false,
        };
        struct nlma nlm = {
            .hdr.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg)),
            .hdr.nlmsg_type = RTM_GETADDR,
-           .hdr.nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST,
+           .hdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_MATCH,
            .ifa.ifa_family = AF_INET,
            .ifa.ifa_index = ifp->index,
        };
 
-       return if_sendnetlink(ifp->ctx, NETLINK_ROUTE, &nlm.hdr,
+       int error = if_sendnetlink(ifp->ctx, NETLINK_ROUTE, &nlm.hdr,
            &_if_addressexists, &ia);
+       if (error == -1)
+               return -1;
+       return ia.ifa_found ? 1 : 0;
 }
 #endif