Merge pull request #10979 from opensourcerouting/pim-ssm-clean

lib, pimd: small cleanup in multicast addr helpers (SSM & co.)

3 files changed, 86 insertions, 12 deletions

diff --git a/lib/prefix.h b/lib/prefix.h
index 816a1517e1..5e03a7b4f5 100644
--- a/lib/prefix.h
+++ b/lib/prefix.h
@@ -585,6 +585,71 @@ static inline int is_default_host_route(const struct prefix *p)
 	return 0;
 }
 
+/* IPv6 scope values, usable for IPv4 too (cf. below) */
+/* clang-format off */
+enum {
+	/* 0: reserved */
+	MCAST_SCOPE_IFACE  = 0x1,
+	MCAST_SCOPE_LINK   = 0x2,
+	MCAST_SCOPE_REALM  = 0x3,
+	MCAST_SCOPE_ADMIN  = 0x4,
+	MCAST_SCOPE_SITE   = 0x5,
+	/* 6-7: unassigned */
+	MCAST_SCOPE_ORG    = 0x8,
+	/* 9-d: unassigned */
+	MCAST_SCOPE_GLOBAL = 0xe,
+	/* f: reserved */
+};
+/* clang-format on */
+
+static inline uint8_t ipv6_mcast_scope(const struct in6_addr *addr)
+{
+	return addr->s6_addr[1] & 0xf;
+}
+
+static inline bool ipv6_mcast_nofwd(const struct in6_addr *addr)
+{
+	return (addr->s6_addr[1] & 0xf) <= MCAST_SCOPE_LINK;
+}
+
+static inline bool ipv6_mcast_ssm(const struct in6_addr *addr)
+{
+	uint32_t bits = ntohl(addr->s6_addr32[0]);
+
+	/* ff3x:0000::/32 */
+	return (bits & 0xfff0ffff) == 0xff300000;
+}
+
+static inline uint8_t ipv4_mcast_scope(const struct in_addr *addr)
+{
+	uint32_t bits = ntohl(addr->s_addr);
+
+	/* 224.0.0.0/24 - link scope */
+	if ((bits & 0xffffff00) == 0xe0000000)
+		return MCAST_SCOPE_LINK;
+	/* 239.0.0.0/8 - org scope */
+	if ((bits & 0xff000000) == 0xef000000)
+		return MCAST_SCOPE_ORG;
+
+	return MCAST_SCOPE_GLOBAL;
+}
+
+static inline bool ipv4_mcast_nofwd(const struct in_addr *addr)
+{
+	uint32_t bits = ntohl(addr->s_addr);
+
+	/* 224.0.0.0/24 */
+	return (bits & 0xffffff00) == 0xe0000000;
+}
+
+static inline bool ipv4_mcast_ssm(const struct in_addr *addr)
+{
+	uint32_t bits = ntohl(addr->s_addr);
+
+	/* 232.0.0.0/8 */
+	return (bits & 0xff000000) == 0xe8000000;
+}
+
 #ifdef _FRR_ATTRIBUTE_PRINTFRR
 #pragma FRR printfrr_ext "%pEA"  (struct ethaddr *)
 
diff --git a/pimd/pim_addr.h b/pimd/pim_addr.h
index e422a2e2da..eca907da37 100644
--- a/pimd/pim_addr.h
+++ b/pimd/pim_addr.h
@@ -34,6 +34,8 @@ typedef struct in_addr pim_addr;
 #define PIM_MAX_BITLEN	IPV4_MAX_BITLEN
 #define PIM_AF_NAME     "ip"
 
+#define PIM_ADDR_FUNCNAME(name) ipv4_##name
+
 union pimprefixptr {
 	prefixtype(pimprefixptr, struct prefix,      p)
 	prefixtype(pimprefixptr, struct prefix_ipv4, p4)
@@ -53,6 +55,8 @@ typedef struct in6_addr pim_addr;
 #define PIM_MAX_BITLEN	IPV6_MAX_BITLEN
 #define PIM_AF_NAME     "ipv6"
 
+#define PIM_ADDR_FUNCNAME(name) ipv6_##name
+
 union pimprefixptr {
 	prefixtype(pimprefixptr, struct prefix,      p)
 	prefixtype(pimprefixptr, struct prefix_ipv6, p6)
@@ -101,6 +105,21 @@ static inline pim_addr pim_addr_from_prefix(union pimprefixconstptr in)
 	return ret;
 }
 
+static inline uint8_t pim_addr_scope(const pim_addr addr)
+{
+	return PIM_ADDR_FUNCNAME(mcast_scope)(&addr);
+}
+
+static inline bool pim_addr_nofwd(const pim_addr addr)
+{
+	return PIM_ADDR_FUNCNAME(mcast_nofwd)(&addr);
+}
+
+static inline bool pim_addr_ssm(const pim_addr addr)
+{
+	return PIM_ADDR_FUNCNAME(mcast_ssm)(&addr);
+}
+
 /* don't use this struct directly, use the pim_sgaddr typedef */
 struct _pim_sgaddr {
 	pim_addr grp;
diff --git a/pimd/pim_ssm.c b/pimd/pim_ssm.c
index 74310474d4..62d6eb8308 100644
--- a/pimd/pim_ssm.c
+++ b/pimd/pim_ssm.c
@@ -70,19 +70,9 @@ void pim_ssm_prefix_list_update(struct pim_instance *pim,
 
 static int pim_is_grp_standard_ssm(struct prefix *group)
 {
-	static int first = 1;
-	static struct prefix group_ssm;
+	pim_addr addr = pim_addr_from_prefix(group);
 
-	if (first) {
-		if (!str2prefix(PIM_SSM_STANDARD_RANGE, &group_ssm))
-			flog_err(EC_LIB_DEVELOPMENT,
-				 "%s: Failure to Read Group Address: %s",
-				 __func__, PIM_SSM_STANDARD_RANGE);
-
-		first = 0;
-	}
-
-	return prefix_match(&group_ssm, group);
+	return pim_addr_ssm(addr);
 }
 
 int pim_is_grp_ssm(struct pim_instance *pim, pim_addr group_addr)