f_flower: Introduce L2TPv3 support

Add support for matching on L2TPv3 session ID.
Session ID can be specified only when ip proto was
set to IPPROTO_L2TP.

L2TPv3 might be transported over IP or over UDP,
this implementation is only about L2TPv3 over IP.
IPv6 is also supported, in this case next header
is set to IPPROTO_L2TP.

Example filter:
  # tc filter add dev eth0 ingress prio 1 protocol ip \
      flower \
        ip_proto l2tp \
        l2tpv3_sid 1234 \
        skip_sw \
      action drop

Reviewed-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Wojciech Drewek <wojciech.drewek@intel.com>
Signed-off-by: David Ahern <dsahern@kernel.org>

1 files changed, 47 insertions, 1 deletions

diff --git a/tc/f_flower.c b/tc/f_flower.c
index 069896a4..4c0a1948 100644
--- a/tc/f_flower.c
+++ b/tc/f_flower.c
@@ -26,6 +26,10 @@
 #include "tc_util.h"
 #include "rt_names.h"
 
+#ifndef IPPROTO_L2TP
+#define IPPROTO_L2TP 115
+#endif
+
 enum flower_matching_flags {
 	FLOWER_IP_FLAGS,
 };
@@ -60,7 +64,7 @@ static void explain(void)
 		"			ppp_proto [ ipv4 | ipv6 | mpls_uc | mpls_mc | PPP_PROTO ]"
 		"			dst_mac MASKED-LLADDR |\n"
 		"			src_mac MASKED-LLADDR |\n"
-		"			ip_proto [tcp | udp | sctp | icmp | icmpv6 | IP-PROTO ] |\n"
+		"			ip_proto [tcp | udp | sctp | icmp | icmpv6 | l2tp | IP-PROTO ] |\n"
 		"			ip_tos MASKED-IP_TOS |\n"
 		"			ip_ttl MASKED-IP_TTL |\n"
 		"			mpls LSE-LIST |\n"
@@ -68,6 +72,7 @@ static void explain(void)
 		"			mpls_tc TC |\n"
 		"			mpls_bos BOS |\n"
 		"			mpls_ttl TTL |\n"
+		"			l2tpv3_sid LSID |\n"
 		"			dst_ip PREFIX |\n"
 		"			src_ip PREFIX |\n"
 		"			dst_port PORT-NUMBER |\n"
@@ -428,6 +433,11 @@ static int flower_parse_ip_proto(char *str, __be16 eth_type, int type,
 		if (eth_type != htons(ETH_P_IPV6))
 			goto err;
 		ip_proto = IPPROTO_ICMPV6;
+	} else if (!strcmp(str, "l2tp")) {
+		if (eth_type != htons(ETH_P_IP) &&
+		    eth_type != htons(ETH_P_IPV6))
+			goto err;
+		ip_proto = IPPROTO_L2TP;
 	} else {
 		ret = get_u8(&ip_proto, str, 16);
 		if (ret)
@@ -646,6 +656,27 @@ static int flower_parse_icmp(char *str, __u16 eth_type, __u8 ip_proto,
 	return flower_parse_u8(str, value_type, mask_type, NULL, NULL, n);
 }
 
+static int flower_parse_l2tpv3(char *str, __u8 ip_proto,
+			       struct nlmsghdr *n)
+{
+	__be32 sid;
+	int ret;
+
+	if (ip_proto != IPPROTO_L2TP) {
+		fprintf(stderr,
+			"Can't set \"l2tpv3_sid\" if ip_proto isn't l2tp\n");
+		return -1;
+	}
+	ret = get_be32(&sid, str, 10);
+	if (ret < 0) {
+		fprintf(stderr, "Illegal \"l2tpv3 session id\"\n");
+		return -1;
+	}
+	addattr32(n, MAX_MSG, TCA_FLOWER_KEY_L2TPV3_SID, sid);
+
+	return 0;
+}
+
 static int flower_port_attr_type(__u8 ip_proto, enum flower_endpoint endpoint)
 {
 	if (ip_proto == IPPROTO_TCP)
@@ -1840,6 +1871,11 @@ static int flower_parse_opt(struct filter_util *qu, char *handle,
 				fprintf(stderr, "Illegal \"icmp code\"\n");
 				return -1;
 			}
+		} else if (!strcmp(*argv, "l2tpv3_sid")) {
+			NEXT_ARG();
+			ret = flower_parse_l2tpv3(*argv, ip_proto, n);
+			if (ret < 0)
+				return -1;
 		} else if (matches(*argv, "arp_tip") == 0) {
 			NEXT_ARG();
 			ret = flower_parse_arp_ip_addr(*argv, eth_type,
@@ -2153,6 +2189,8 @@ static void flower_print_ip_proto(__u8 *p_ip_proto,
 		sprintf(out, "icmp");
 	else if (ip_proto == IPPROTO_ICMPV6)
 		sprintf(out, "icmpv6");
+	else if (ip_proto == IPPROTO_L2TP)
+		sprintf(out, "l2tp");
 	else
 		sprintf(out, "%02x", ip_proto);
 
@@ -2880,6 +2918,14 @@ static int flower_print_opt(struct filter_util *qu, FILE *f,
 		flower_print_masked_u8("icmp_code", tb[nl_type],
 				       tb[nl_mask_type], NULL);
 
+	if (tb[TCA_FLOWER_KEY_L2TPV3_SID]) {
+		struct rtattr *attr = tb[TCA_FLOWER_KEY_L2TPV3_SID];
+
+		print_nl();
+		print_uint(PRINT_ANY, "l2tpv3_sid", "  l2tpv3_sid %u",
+			   rta_getattr_be32(attr));
+	}
+
 	flower_print_ip4_addr("arp_sip", tb[TCA_FLOWER_KEY_ARP_SIP],
 			     tb[TCA_FLOWER_KEY_ARP_SIP_MASK]);
 	flower_print_ip4_addr("arp_tip", tb[TCA_FLOWER_KEY_ARP_TIP],