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fix(pfcp): match a rule only within its own address family

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`ogs_pfcp_pdr_rule_find_by_packet()` compares `addr_len` bytes of the rule's
address, where `addr_len` is the *packet's* length. The rule's own family flags
(`ipv4_src`, `ipv4_dst`, `ipv6_src`, `ipv6_dst`) were never consulted, so the
memcmp compared only the first four bytes of an IPv6 address against an IPv4
packet, and the first four bytes of an IPv4 address against an IPv6 packet.

The SMF installs `permit out 58 from ff02::2/128 to assigned` for every session,
so an IPv4 packet whose source begins ff 02 00 00 — 255.2.0.0 — matched that RS
rule and was forwarded to the CP function's TEID instead of the N6 interface,
dropping out of the default flow's usage statistics.

Skip a rule whose address family differs from the packet's. Rules that name no
address (both flags zero) still match either family.
This commit is contained in:
PerryLink 2026-10-17 10:00:25 +08:00 • committed by Sukchan Lee
parent f125568440
commit d43dc8011c
2 changed files with 84 additions and 0 deletions
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12
lib/pfcp/rule-match.c
View file

@ -381,6 +381,18 @@ ogs_pfcp_rule_t *ogs_pfcp_pdr_rule_find_by_packet(
be32toh(ipfw->ip.dst.mask[2]),
be32toh(ipfw->ip.dst.mask[3]));
/*
* addr_len is the packet's address length, so comparing only that many
* bytes of the rule matches the first four bytes of an IPv6 address
* against an IPv4 packet, and the reverse. A rule that names an address
* of the other family cannot match this packet.
*/
if ((addr_len == OGS_IPV4_LEN &&
(ipfw->ipv6_src || ipfw->ipv6_dst)) ||
(addr_len == OGS_IPV6_LEN &&
(ipfw->ipv4_src || ipfw->ipv4_dst)))
continue;
for (k = 0; k < 4; k++) {
src_mask[k] = src_addr[k] & ipfw->ip.src.mask[k];
dst_mask[k] = dst_addr[k] & ipfw->ip.dst.mask[k];

72
tests/unit/pfcp-rule-test.c
View file

@ -592,6 +592,77 @@ static void test_remove_referenced_rules(abts_case *tc, void *data)
ogs_pfcp_pool_final(&sess);
}
static void test_find_by_packet_address_family(abts_case *tc, void *data)
{
ogs_pfcp_sess_t sess;
ogs_pfcp_pdr_t *pdr = NULL;
ogs_pfcp_rule_t *rule = NULL;
ogs_pkbuf_t *pkbuf = NULL;
struct ip *ip4 = NULL;
struct ip6_hdr *ip6 = NULL;
uint8_t *p = NULL;
memset(&sess, 0, sizeof(sess));
ogs_pfcp_pool_init(&sess);
pdr = ogs_pfcp_pdr_add(&sess);
/*
* The RS rule the SMF installs for every 5G session
* (src/smf/npcf-handler.c): "permit out 58 from ff02::2/128 to assigned"
*/
rule = ogs_pfcp_rule_add(pdr);
rule->ipfw.proto = 58;
rule->ipfw.ipv6_src = 1;
/* ff02::2 in address order, as ogs-ipfw.c copies it */
((uint8_t *)&rule->ipfw.ip.src.addr[0])[0] = 0xff;
((uint8_t *)&rule->ipfw.ip.src.addr[0])[1] = 0x02;
((uint8_t *)&rule->ipfw.ip.src.addr[3])[3] = 0x02;
rule->ipfw.ip.src.mask[0] = 0xffffffff;
rule->ipfw.ip.src.mask[1] = 0xffffffff;
rule->ipfw.ip.src.mask[2] = 0xffffffff;
rule->ipfw.ip.src.mask[3] = 0xffffffff;
/* An IPv4 packet whose first four source bytes equal ff02::2's must not match.
ip_src.s_addr is already in network order, so the bytes are what is compared. */
pkbuf = ogs_pkbuf_alloc(NULL, 20 + 8);
ogs_assert(pkbuf);
pkbuf->len = 20 + 8;
ip4 = (struct ip *)pkbuf->data;
memset(ip4, 0, 20 + 8);
ip4->ip_v = 4;
ip4->ip_hl = 5;
ip4->ip_p = 58;
ip4->ip_len = htons(20 + 8);
((uint8_t *)&ip4->ip_src.s_addr)[0] = 0xff; /* 255.2.0.0 */
((uint8_t *)&ip4->ip_src.s_addr)[1] = 0x02;
((uint8_t *)&ip4->ip_dst.s_addr)[0] = 0x0a;
((uint8_t *)&ip4->ip_dst.s_addr)[1] = 0x2d;
ABTS_PTR_EQUAL(tc,
NULL, ogs_pfcp_pdr_rule_find_by_packet(pdr, pkbuf));
ogs_pkbuf_free(pkbuf);
/* An IPv6 packet from ff02::2 must match */
pkbuf = ogs_pkbuf_alloc(NULL, 40 + 8);
ogs_assert(pkbuf);
pkbuf->len = 40 + 8;
ip6 = (struct ip6_hdr *)pkbuf->data;
memset(ip6, 0, 40 + 8);
ip6->ip6_vfc = 0x60;
ip6->ip6_nxt = 58;
ip6->ip6_plen = htons(8);
p = (uint8_t *)&ip6->ip6_src;
p[0] = 0xff; p[1] = 0x02; p[15] = 0x02;
ABTS_PTR_EQUAL(tc,
rule, ogs_pfcp_pdr_rule_find_by_packet(pdr, pkbuf));
ogs_pkbuf_free(pkbuf);
ogs_pfcp_sess_clear(&sess);
ogs_pfcp_pool_final(&sess);
}
abts_suite *test_pfcp_rule(abts_suite *suite)
{
ogs_log_level_e level = ogs_log_get_domain_level(__ogs_pfcp_domain);
@ -614,6 +685,7 @@ abts_suite *test_pfcp_rule(abts_suite *suite)
abts_run_test(suite, test_far_f_teid_owner, NULL);
abts_run_test(suite, test_far_rekey_collision, NULL);
abts_run_test(suite, test_remove_referenced_rules, NULL);
abts_run_test(suite, test_find_by_packet_address_family, NULL);
ogs_pfcp_context_final();
ogs_app_context_final();