[dpdk-dev] [PATCH 1/3] examples/ipsec-secgw: fix invalid packet length

[Konstantin Ananyev <konstantin.ananyev@intel.com>]

for packets smaller then 64B some NICs reports pkt_len=64B.
As ipsec-secgw (and librte_ipsec) relies on pkt_len value to determine
payload length, that causes problems for small packets.
To fix the issue, check that pkt_len matches values in IPv4/IPv6 header
and re-adjust pkt_len if necessary.

Fixes: 906257e965b7 ("examples/ipsec-secgw: support IPv6")
Fixes: d299106e8e31 ("examples/ipsec-secgw: add IPsec sample application")
Cc: stable@dpdk.org

Signed-off-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
---
 examples/ipsec-secgw/ipsec-secgw.c | 59 +++++++++++++++++++++++-------
 1 file changed, 46 insertions(+), 13 deletions(-)

diff --git a/examples/ipsec-secgw/ipsec-secgw.c b/examples/ipsec-secgw/ipsec-secgw.c
index 478dd80c2..1d1855f50 100644
--- a/examples/ipsec-secgw/ipsec-secgw.c
+++ b/examples/ipsec-secgw/ipsec-secgw.c
@@ -229,35 +229,68 @@ static struct rte_eth_conf port_conf = {
 
 static struct socket_ctx socket_ctx[NB_SOCKETS];
 
+static inline void
+adjust_ipv4_pktlen(struct rte_mbuf *m, const struct ipv4_hdr *iph,
+	uint32_t l2_len)
+{
+	uint32_t plen, trim;
+
+	plen = rte_be_to_cpu_16(iph->total_length) + l2_len;
+	if (plen < m->pkt_len) {
+		trim = m->pkt_len - plen;
+		rte_pktmbuf_trim(m, trim);
+	}
+}
+
+static inline void
+adjust_ipv6_pktlen(struct rte_mbuf *m, const struct ipv6_hdr *iph,
+	uint32_t l2_len)
+{
+	uint32_t plen, trim;
+
+	plen = rte_be_to_cpu_16(iph->payload_len) + sizeof(*iph) + l2_len;
+	if (plen < m->pkt_len) {
+		trim = m->pkt_len - plen;
+		rte_pktmbuf_trim(m, trim);
+	}
+}
+
 static inline void
 prepare_one_packet(struct rte_mbuf *pkt, struct ipsec_traffic *t)
 {
-	uint8_t *nlp;
-	struct ether_hdr *eth;
+	const struct ether_hdr *eth;
+	const struct ipv4_hdr *iph4;
+	const struct ipv6_hdr *iph6;
 
-	eth = rte_pktmbuf_mtod(pkt, struct ether_hdr *);
+	eth = rte_pktmbuf_mtod(pkt, const struct ether_hdr *);
 	if (eth->ether_type == rte_cpu_to_be_16(ETHER_TYPE_IPv4)) {
-		nlp = (uint8_t *)rte_pktmbuf_adj(pkt, ETHER_HDR_LEN);
-		nlp = RTE_PTR_ADD(nlp, offsetof(struct ip, ip_p));
-		if (*nlp == IPPROTO_ESP)
+
+		iph4 = (const struct ipv4_hdr *)rte_pktmbuf_adj(pkt,
+			ETHER_HDR_LEN);
+		adjust_ipv4_pktlen(pkt, iph4, 0);
+
+		if (iph4->next_proto_id == IPPROTO_ESP)
 			t->ipsec.pkts[(t->ipsec.num)++] = pkt;
 		else {
-			t->ip4.data[t->ip4.num] = nlp;
+			t->ip4.data[t->ip4.num] = &iph4->next_proto_id;
 			t->ip4.pkts[(t->ip4.num)++] = pkt;
 		}
 		pkt->l2_len = 0;
-		pkt->l3_len = sizeof(struct ip);
+		pkt->l3_len = sizeof(*iph4);
 	} else if (eth->ether_type == rte_cpu_to_be_16(ETHER_TYPE_IPv6)) {
-		nlp = (uint8_t *)rte_pktmbuf_adj(pkt, ETHER_HDR_LEN);
-		nlp = RTE_PTR_ADD(nlp, offsetof(struct ip6_hdr, ip6_nxt));
-		if (*nlp == IPPROTO_ESP)
+
+		iph6 = (const struct ipv6_hdr *)rte_pktmbuf_adj(pkt,
+			ETHER_HDR_LEN);
+		adjust_ipv6_pktlen(pkt, iph6, 0);
+
+		if (iph6->proto == IPPROTO_ESP)
 			t->ipsec.pkts[(t->ipsec.num)++] = pkt;
 		else {
-			t->ip6.data[t->ip6.num] = nlp;
+			t->ip6.data[t->ip6.num] = &iph6->proto;
 			t->ip6.pkts[(t->ip6.num)++] = pkt;
 		}
 		pkt->l2_len = 0;
-		pkt->l3_len = sizeof(struct ip6_hdr);
+		pkt->l3_len = sizeof(*iph6);
 	} else {
 		/* Unknown/Unsupported type, drop the packet */
 		RTE_LOG(ERR, IPSEC, "Unsupported packet type 0x%x\n",
-- 
2.17.1