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

9 files changed, 63 insertions, 96 deletions

diff --git a/sys/net/ieee8023ad_lacp.c b/sys/net/ieee8023ad_lacp.c
index 1042de6ab819..b023c6caa119 100644
--- a/sys/net/ieee8023ad_lacp.c
+++ b/sys/net/ieee8023ad_lacp.c
@@ -522,11 +522,7 @@ lacp_port_create(struct lagg_port *lgp)
 	boolean_t active = TRUE; /* XXX should be configurable */
 	boolean_t fast = FALSE; /* XXX should be configurable */
 
-	bzero((char *)&sdl, sizeof(sdl));
-	sdl.sdl_len = sizeof(sdl);
-	sdl.sdl_family = AF_LINK;
-	sdl.sdl_index = ifp->if_index;
-	sdl.sdl_type = IFT_ETHER;
+	link_init_sdl(ifp, (struct sockaddr *)&sdl, IFT_ETHER);
 	sdl.sdl_alen = ETHER_ADDR_LEN;
 
 	bcopy(&ethermulticastaddr_slowprotocols,
diff --git a/sys/net/if.c b/sys/net/if.c
index 75c8e3ff4eb2..cef3dd35f6a9 100644
--- a/sys/net/if.c
+++ b/sys/net/if.c
@@ -1888,6 +1888,38 @@ link_rtrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
 	}
 }
 
+struct sockaddr_dl *
+link_alloc_sdl(size_t size, int flags)
+{
+
+	return (malloc(size, M_TEMP, flags));
+}
+
+void
+link_free_sdl(struct sockaddr *sa)
+{
+	free(sa, M_TEMP);
+}
+
+/*
+ * Fills in given sdl with interface basic info.
+ * Returns pointer to filled sdl.
+ */
+struct sockaddr_dl *
+link_init_sdl(struct ifnet *ifp, struct sockaddr *paddr, u_char iftype)
+{
+	struct sockaddr_dl *sdl;
+
+	sdl = (struct sockaddr_dl *)paddr;
+	memset(sdl, 0, sizeof(struct sockaddr_dl));
+	sdl->sdl_len = sizeof(struct sockaddr_dl);
+	sdl->sdl_family = AF_LINK;
+	sdl->sdl_index = ifp->if_index;
+	sdl->sdl_type = iftype;
+
+	return (sdl);
+}
+
 /*
  * Mark an interface down and notify protocols of
  * the transition.
@@ -2938,6 +2970,7 @@ if_addmulti(struct ifnet *ifp, struct sockaddr *sa,
 {
 	struct ifmultiaddr *ifma, *ll_ifma;
 	struct sockaddr *llsa;
+	struct sockaddr_dl sdl;
 	int error;
 
 	/*
@@ -2957,12 +2990,18 @@ if_addmulti(struct ifnet *ifp, struct sockaddr *sa,
 	/*
 	 * The address isn't already present; resolve the protocol address
 	 * into a link layer address, and then look that up, bump its
-	 * refcount or allocate an ifma for that also.  If 'llsa' was
-	 * returned, we will need to free it later.
+	 * refcount or allocate an ifma for that also.
+	 * Most link layer resolving functions returns address data which
+	 * fits inside default sockaddr_dl structure. However callback
+	 * can allocate another sockaddr structure, in that case we need to
+	 * free it later.
 	 */
 	llsa = NULL;
 	ll_ifma = NULL;
 	if (ifp->if_resolvemulti != NULL) {
+		/* Provide called function with buffer size information */
+		sdl.sdl_len = sizeof(sdl);
+		llsa = (struct sockaddr *)&sdl;
 		error = ifp->if_resolvemulti(ifp, &llsa, sa);
 		if (error)
 			goto unlock_out;
@@ -3026,14 +3065,14 @@ if_addmulti(struct ifnet *ifp, struct sockaddr *sa,
 		(void) (*ifp->if_ioctl)(ifp, SIOCADDMULTI, 0);
 	}
 
-	if (llsa != NULL)
-		free(llsa, M_IFMADDR);
+	if ((llsa != NULL) && (llsa != (struct sockaddr *)&sdl))
+		link_free_sdl(llsa);
 
 	return (0);
 
 free_llsa_out:
-	if (llsa != NULL)
-		free(llsa, M_IFMADDR);
+	if ((llsa != NULL) && (llsa != (struct sockaddr *)&sdl))
+		link_free_sdl(llsa);
 
 unlock_out:
 	IF_ADDR_WUNLOCK(ifp);
diff --git a/sys/net/if_arcsubr.c b/sys/net/if_arcsubr.c
index 49c2dd3de685..6cec6d959d37 100644
--- a/sys/net/if_arcsubr.c
+++ b/sys/net/if_arcsubr.c
@@ -786,14 +786,7 @@ arc_resolvemulti(struct ifnet *ifp, struct sockaddr **llsa,
 		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_ARCNET;
+		sdl = link_init_sdl(ifp, *llsa, IFT_ETHER);
 		sdl->sdl_alen = ARC_ADDR_LEN;
 		*LLADDR(sdl) = 0;
 		*llsa = (struct sockaddr *)sdl;
@@ -814,14 +807,7 @@ arc_resolvemulti(struct ifnet *ifp, struct sockaddr **llsa,
 		}
 		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_ARCNET;
+		sdl = link_init_sdl(ifp, *llsa, IFT_ETHER);
 		sdl->sdl_alen = ARC_ADDR_LEN;
 		*LLADDR(sdl) = 0;
 		*llsa = (struct sockaddr *)sdl;
diff --git a/sys/net/if_dl.h b/sys/net/if_dl.h
index 64f4b56d76e6..8b4e00790eb6 100644
--- a/sys/net/if_dl.h
+++ b/sys/net/if_dl.h
@@ -69,6 +69,12 @@ struct sockaddr_dl {
 #define LLADDR(s) ((caddr_t)((s)->sdl_data + (s)->sdl_nlen))
 #define LLINDEX(s) ((s)->sdl_index)
 
+
+struct ifnet;
+struct sockaddr_dl *link_alloc_sdl(size_t, int);
+void link_free_sdl(struct sockaddr *sa);
+struct sockaddr_dl *link_init_sdl(struct ifnet *, struct sockaddr *, u_char);
+
 #ifndef _KERNEL
 
 #include <sys/cdefs.h>
diff --git a/sys/net/if_ethersubr.c b/sys/net/if_ethersubr.c
index 04b94defc956..ec29b693d7e4 100644
--- a/sys/net/if_ethersubr.c
+++ b/sys/net/if_ethersubr.c
@@ -1168,14 +1168,7 @@ ether_resolvemulti(struct ifnet *ifp, struct sockaddr **llsa,
 		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_ETHER;
+		sdl = link_init_sdl(ifp, *llsa, IFT_ETHER);
 		sdl->sdl_alen = ETHER_ADDR_LEN;
 		e_addr = LLADDR(sdl);
 		ETHER_MAP_IP_MULTICAST(&sin->sin_addr, e_addr);
@@ -1197,14 +1190,7 @@ ether_resolvemulti(struct ifnet *ifp, struct sockaddr **llsa,
 		}
 		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_ETHER;
+		sdl = link_init_sdl(ifp, *llsa, IFT_ETHER);
 		sdl->sdl_alen = ETHER_ADDR_LEN;
 		e_addr = LLADDR(sdl);
 		ETHER_MAP_IPV6_MULTICAST(&sin6->sin6_addr, e_addr);
diff --git a/sys/net/if_fddisubr.c b/sys/net/if_fddisubr.c
index 2f03bb7e5feb..2bb818bd702e 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;
diff --git a/sys/net/if_iso88025subr.c b/sys/net/if_iso88025subr.c
index 825b220a1311..593c5ab4bd83 100644
--- a/sys/net/if_iso88025subr.c
+++ b/sys/net/if_iso88025subr.c
@@ -721,14 +721,7 @@ iso88025_resolvemulti (ifp, llsa, 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_ISO88025;
+		sdl = link_init_sdl(ifp, *llsa, IFT_ISO88025);
 		sdl->sdl_alen = ISO88025_ADDR_LEN;
 		e_addr = LLADDR(sdl);
 		ETHER_MAP_IP_MULTICAST(&sin->sin_addr, e_addr);
@@ -751,14 +744,7 @@ iso88025_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_ISO88025;
+		sdl = link_init_sdl(ifp, *llsa, IFT_ISO88025);
 		sdl->sdl_alen = ISO88025_ADDR_LEN;
 		e_addr = LLADDR(sdl);
 		ETHER_MAP_IPV6_MULTICAST(&sin6->sin6_addr, e_addr);
diff --git a/sys/net/if_lagg.c b/sys/net/if_lagg.c
index beae0b616b20..c9000640e4e2 100644
--- a/sys/net/if_lagg.c
+++ b/sys/net/if_lagg.c
@@ -1214,12 +1214,8 @@ lagg_ether_cmdmulti(struct lagg_port *lp, int set)
 
 	LAGG_WLOCK_ASSERT(sc);
 
-	bzero((char *)&sdl, sizeof(sdl));
-	sdl.sdl_len = sizeof(sdl);
-	sdl.sdl_family = AF_LINK;
-	sdl.sdl_type = IFT_ETHER;
+	link_init_sdl(ifp, (struct sockaddr *)&sdl, IFT_ETHER);
 	sdl.sdl_alen = ETHER_ADDR_LEN;
-	sdl.sdl_index = ifp->if_index;
 
 	if (set) {
 		TAILQ_FOREACH(ifma, &scifp->if_multiaddrs, ifma_link) {
diff --git a/sys/ofed/drivers/infiniband/ulp/ipoib/ipoib_main.c b/sys/ofed/drivers/infiniband/ulp/ipoib/ipoib_main.c
index bae1740ae7bd..52a03d2a7913 100644
--- a/sys/ofed/drivers/infiniband/ulp/ipoib/ipoib_main.c
+++ b/sys/ofed/drivers/infiniband/ulp/ipoib/ipoib_main.c
@@ -1490,14 +1490,7 @@ ipoib_resolvemulti(struct ifnet *ifp, struct sockaddr **llsa,
 		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_INFINIBAND;
+		sdl = link_init_sdl(ifp, *llsa, IFT_INFINIBAND);
 		sdl->sdl_alen = INFINIBAND_ALEN;
 		e_addr = LLADDR(sdl);
 		ip_ib_mc_map(sin->sin_addr.s_addr, ifp->if_broadcastaddr,
@@ -1517,14 +1510,7 @@ ipoib_resolvemulti(struct ifnet *ifp, struct sockaddr **llsa,
 			return EADDRNOTAVAIL;
 		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_INFINIBAND;
+		sdl = link_init_sdl(ifp, *llsa, IFT_INFINIBAND);
 		sdl->sdl_alen = INFINIBAND_ALEN;
 		e_addr = LLADDR(sdl);
 		ipv6_ib_mc_map(&sin6->sin6_addr, ifp->if_broadcastaddr, e_addr);