Merge branch 'bridge-PIM-hello'

Nikolay Aleksandrov says:

====================
bridge: add support for PIM hello router ports

The first 3 patches of this set do minor cleanups and add some helpers to
the PIM header file. Patch 4 adds a way to detect mcast router ports via
PIM hello messages, they're marked as temporary and are not considered for
querier. There's more detailed information in patch 4's commit message.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/pim.h

@@ -1,6 +1,7 @@
 #ifndef __LINUX_PIM_H
 #define __LINUX_PIM_H
 
+#include <linux/skbuff.h>
 #include <asm/byteorder.h>
 
 /* Message types - V1 */
@@ -9,24 +10,86 @@
 
 /* Message types - V2 */
 #define PIM_VERSION		2
-#define PIM_REGISTER		1
+
+/* RFC7761, sec 4.9:
+ *  Type
+ *        Types for specific PIM messages.  PIM Types are:
+ *
+ *  Message Type                          Destination
+ *  ---------------------------------------------------------------------
+ *  0 = Hello                             Multicast to ALL-PIM-ROUTERS
+ *  1 = Register                          Unicast to RP
+ *  2 = Register-Stop                     Unicast to source of Register
+ *                                        packet
+ *  3 = Join/Prune                        Multicast to ALL-PIM-ROUTERS
+ *  4 = Bootstrap                         Multicast to ALL-PIM-ROUTERS
+ *  5 = Assert                            Multicast to ALL-PIM-ROUTERS
+ *  6 = Graft (used in PIM-DM only)       Unicast to RPF'(S)
+ *  7 = Graft-Ack (used in PIM-DM only)   Unicast to source of Graft
+ *                                        packet
+ *  8 = Candidate-RP-Advertisement        Unicast to Domain's BSR
+ */
+enum {
+	PIM_TYPE_HELLO,
+	PIM_TYPE_REGISTER,
+	PIM_TYPE_REGISTER_STOP,
+	PIM_TYPE_JOIN_PRUNE,
+	PIM_TYPE_BOOTSTRAP,
+	PIM_TYPE_ASSERT,
+	PIM_TYPE_GRAFT,
+	PIM_TYPE_GRAFT_ACK,
+	PIM_TYPE_CANDIDATE_RP_ADV
+};
 
 #define PIM_NULL_REGISTER	cpu_to_be32(0x40000000)
 
-static inline bool ipmr_pimsm_enabled(void)
-{
-	return IS_BUILTIN(CONFIG_IP_PIMSM_V1) || IS_BUILTIN(CONFIG_IP_PIMSM_V2);
-}
+/* RFC7761, sec 4.9:
+ * The PIM header common to all PIM messages is:
+ *   0                   1                   2                   3
+ *   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *  |PIM Ver| Type  |   Reserved    |           Checksum            |
+ *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ */
+struct pimhdr {
+	__u8	type;
+	__u8	reserved;
+	__be16	csum;
+};
 
 /* PIMv2 register message header layout (ietf-draft-idmr-pimvsm-v2-00.ps */
-struct pimreghdr
-{
+struct pimreghdr {
 	__u8	type;
 	__u8	reserved;
 	__be16	csum;
 	__be32	flags;
 };
 
-struct sk_buff;
-extern int pim_rcv_v1(struct sk_buff *);
+int pim_rcv_v1(struct sk_buff *skb);
+
+static inline bool ipmr_pimsm_enabled(void)
+{
+	return IS_BUILTIN(CONFIG_IP_PIMSM_V1) || IS_BUILTIN(CONFIG_IP_PIMSM_V2);
+}
+
+static inline struct pimhdr *pim_hdr(const struct sk_buff *skb)
+{
+	return (struct pimhdr *)skb_transport_header(skb);
+}
+
+static inline u8 pim_hdr_version(const struct pimhdr *pimhdr)
+{
+	return pimhdr->type >> 4;
+}
+
+static inline u8 pim_hdr_type(const struct pimhdr *pimhdr)
+{
+	return pimhdr->type & 0xf;
+}
+
+/* check if the address is 224.0.0.13, RFC7761 sec 4.3.1 */
+static inline bool pim_ipv4_all_pim_routers(__be32 addr)
+{
+	return addr == htonl(0xE000000D);
+}
 #endif

net/bridge/br_multicast.c

@@ -25,6 +25,7 @@
 #include <linux/slab.h>
 #include <linux/timer.h>
 #include <linux/inetdevice.h>
+#include <linux/mroute.h>
 #include <net/ip.h>
 #if IS_ENABLED(CONFIG_IPV6)
 #include <net/ipv6.h>
@@ -1638,6 +1639,21 @@ static void br_multicast_err_count(const struct net_bridge *br,
 	u64_stats_update_end(&pstats->syncp);
 }
 
+static void br_multicast_pim(struct net_bridge *br,
+			     struct net_bridge_port *port,
+			     const struct sk_buff *skb)
+{
+	unsigned int offset = skb_transport_offset(skb);
+	struct pimhdr *pimhdr, _pimhdr;
+
+	pimhdr = skb_header_pointer(skb, offset, sizeof(_pimhdr), &_pimhdr);
+	if (!pimhdr || pim_hdr_version(pimhdr) != PIM_VERSION ||
+	    pim_hdr_type(pimhdr) != PIM_TYPE_HELLO)
+		return;
+
+	br_multicast_mark_router(br, port);
+}
+
 static int br_multicast_ipv4_rcv(struct net_bridge *br,
 				 struct net_bridge_port *port,
 				 struct sk_buff *skb,
@@ -1650,8 +1666,12 @@ static int br_multicast_ipv4_rcv(struct net_bridge *br,
 	err = ip_mc_check_igmp(skb, &skb_trimmed);
 
 	if (err == -ENOMSG) {
-		if (!ipv4_is_local_multicast(ip_hdr(skb)->daddr))
+		if (!ipv4_is_local_multicast(ip_hdr(skb)->daddr)) {
 			BR_INPUT_SKB_CB(skb)->mrouters_only = 1;
+		} else if (pim_ipv4_all_pim_routers(ip_hdr(skb)->daddr)) {
+			if (ip_hdr(skb)->protocol == IPPROTO_PIM)
+				br_multicast_pim(br, port, skb);
+		}
 		return 0;
 	} else if (err < 0) {
 		br_multicast_err_count(br, port, skb->protocol);

net/ipv4/ipmr.c

@@ -2053,7 +2053,7 @@ static int pim_rcv(struct sk_buff *skb)
 		goto drop;
 
 	pim = (struct pimreghdr *)skb_transport_header(skb);
-	if (pim->type != ((PIM_VERSION << 4) | (PIM_REGISTER)) ||
+	if (pim->type != ((PIM_VERSION << 4) | (PIM_TYPE_REGISTER)) ||
 	    (pim->flags & PIM_NULL_REGISTER) ||
 	    (ip_compute_csum((void *)pim, sizeof(*pim)) != 0 &&
 	     csum_fold(skb_checksum(skb, 0, skb->len, 0))))

net/ipv6/ip6mr.c

@@ -636,7 +636,7 @@ static int pim6_rcv(struct sk_buff *skb)
 		goto drop;
 
 	pim = (struct pimreghdr *)skb_transport_header(skb);
-	if (pim->type != ((PIM_VERSION << 4) | PIM_REGISTER) ||
+	if (pim->type != ((PIM_VERSION << 4) | PIM_TYPE_REGISTER) ||
 	    (pim->flags & PIM_NULL_REGISTER) ||
 	    (csum_ipv6_magic(&ipv6_hdr(skb)->saddr, &ipv6_hdr(skb)->daddr,
 			     sizeof(*pim), IPPROTO_PIM,