Simplify filling sockaddr_dl structure for if_resolvemulti()

callback providers. link_init_sdl() function can be used to
fill most of the parameters. Use caller stack instead of
allocation / freing memory for each request. Do not drop support
for extra-long (probably non-existing) link-layer protocols by
introducing link_alloc_sdl() (used by if_resolvemulti() callback)
and link_free_sdl() (used by caller).
Since this change breaks KBI, MFC requires slightly different approach
(link_init_sdl() auto-allocating buffer if necessary to handle cases
 with unmodified if_resolvemulti() callers).

MFC after:	2 weeks

1 files changed, 2 insertions, 16 deletions

diff --git a/sys/net/if_fddisubr.c b/sys/net/if_fddisubr.c
index 2f03bb7..2bb818b 100644
--- a/sys/net/if_fddisubr.c
+++ b/sys/net/if_fddisubr.c
@@ -729,14 +729,7 @@ fddi_resolvemulti(ifp, llsa, sa)
 		sin = (struct sockaddr_in *)sa;
 		if (!IN_MULTICAST(ntohl(sin->sin_addr.s_addr)))
 			return (EADDRNOTAVAIL);
-		sdl = malloc(sizeof *sdl, M_IFMADDR,
-		       M_NOWAIT | M_ZERO);
-		if (sdl == NULL)
-			return (ENOMEM);
-		sdl->sdl_len = sizeof *sdl;
-		sdl->sdl_family = AF_LINK;
-		sdl->sdl_index = ifp->if_index;
-		sdl->sdl_type = IFT_FDDI;
+		sdl = link_init_sdl(ifp, *llsa, IFT_FDDI);
 		sdl->sdl_nlen = 0;
 		sdl->sdl_alen = FDDI_ADDR_LEN;
 		sdl->sdl_slen = 0;
@@ -760,14 +753,7 @@ fddi_resolvemulti(ifp, llsa, sa)
 		}
 		if (!IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
 			return (EADDRNOTAVAIL);
-		sdl = malloc(sizeof *sdl, M_IFMADDR,
-		       M_NOWAIT | M_ZERO);
-		if (sdl == NULL)
-			return (ENOMEM);
-		sdl->sdl_len = sizeof *sdl;
-		sdl->sdl_family = AF_LINK;
-		sdl->sdl_index = ifp->if_index;
-		sdl->sdl_type = IFT_FDDI;
+		sdl = link_init_sdl(ifp, *llsa, IFT_FDDI);
 		sdl->sdl_nlen = 0;
 		sdl->sdl_alen = FDDI_ADDR_LEN;
 		sdl->sdl_slen = 0;