zebra: fix FreeBSD warning on fresh OS boot

[mirror_frr.git] / zebra / kernel_socket.c

diff --git a/zebra/kernel_socket.c b/zebra/kernel_socket.c
index 1f82c1d591c1a4065a0044edafb69666a677b0e8..29d2b1f45f92fc8b2e139d81f3479306f124a971 100644 (file)
--- a/zebra/kernel_socket.c
+++ b/zebra/kernel_socket.c
@@ -250,6 +250,7 @@ static inline int af_check(int family)
 size_t _rta_get(caddr_t sap, void *destp, size_t destlen, bool checkaf)
 {
        struct sockaddr *sa = (struct sockaddr *)sap;
+       struct sockaddr_dl *sdl;
        uint8_t *dest = destp;
        size_t tlen, copylen;
 
@@ -263,6 +264,17 @@ size_t _rta_get(caddr_t sap, void *destp, size_t destlen, bool checkaf)
        if (copylen > 0 && dest != NULL) {
                if (checkaf && af_check(sa->sa_family) == 0)
                        return tlen;
+               /*
+                * Handle sockaddr_dl corner case:
+                * RTA_NETMASK might be AF_LINK, but it doesn't anything
+                * relevant (e.g. zeroed out fields). Check for this
+                * case and avoid warning log message.
+                */
+               if (sa->sa_family == AF_LINK) {
+                       sdl = (struct sockaddr_dl *)sa;
+                       if (sdl->sdl_index == 0 || sdl->sdl_nlen == 0)
+                               copylen = sizeof(*sdl) - sizeof(sdl->sdl_data);
+               }
 
                if (copylen > destlen) {
                        zlog_warn("%s: destination buffer too small (%lu vs %lu)",