From: Michael Pfeiffer <michael.pfeiffer@tu-ilmenau.de>
Date: Tue, 1 Sep 2020 09:47:55 +0000 (+0200)
Subject: net: calculate checksum of packet with IPv4 options
X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=ac0ad5eff81d50170261845b3b805885011ef929;p=dpdk.git

net: calculate checksum of packet with IPv4 options

Currently, rte_ipv4_cksum() and rte_ipv4_udptcp_cksum() assume all IPv4
headers have sizeof(struct rte_ipv4_hdr) bytes. This is not true for
those (rare) packets with IPv4 options. Thus, both IPv4 and TCP/UDP
checksums are calculated wrong.

This patch fixes the issue by using the actual IPv4 header length from
the packet's IHL field.

Signed-off-by: Michael Pfeiffer <michael.pfeiffer@tu-ilmenau.de>
Reviewed-by: Andrew Rybchenko <arybchenko@solarflare.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
---

diff --git a/lib/librte_net/rte_ip.h b/lib/librte_net/rte_ip.h
index fcd1eb342d..bb55ebb6fa 100644
--- a/lib/librte_net/rte_ip.h
+++ b/lib/librte_net/rte_ip.h
@@ -269,7 +269,7 @@ static inline uint16_t
 rte_ipv4_cksum(const struct rte_ipv4_hdr *ipv4_hdr)
 {
 	uint16_t cksum;
-	cksum = rte_raw_cksum(ipv4_hdr, sizeof(struct rte_ipv4_hdr));
+	cksum = rte_raw_cksum(ipv4_hdr, (ipv4_hdr->version_ihl & 0xf) * 4);
 	return (uint16_t)~cksum;
 }
 
@@ -302,6 +302,9 @@ rte_ipv4_phdr_cksum(const struct rte_ipv4_hdr *ipv4_hdr, uint64_t ol_flags)
 		uint16_t len;      /* L4 length. */
 	} psd_hdr;
 
+	uint32_t l3_len;
+	uint8_t ip_hdr_len;
+
 	psd_hdr.src_addr = ipv4_hdr->src_addr;
 	psd_hdr.dst_addr = ipv4_hdr->dst_addr;
 	psd_hdr.zero = 0;
@@ -309,9 +312,9 @@ rte_ipv4_phdr_cksum(const struct rte_ipv4_hdr *ipv4_hdr, uint64_t ol_flags)
 	if (ol_flags & PKT_TX_TCP_SEG) {
 		psd_hdr.len = 0;
 	} else {
-		psd_hdr.len = rte_cpu_to_be_16(
-			(uint16_t)(rte_be_to_cpu_16(ipv4_hdr->total_length)
-				- sizeof(struct rte_ipv4_hdr)));
+		l3_len = rte_be_to_cpu_16(ipv4_hdr->total_length);
+		ip_hdr_len = (ipv4_hdr->version_ihl & 0xf) * 4;
+		psd_hdr.len = rte_cpu_to_be_16((uint16_t)(l3_len - ip_hdr_len));
 	}
 	return rte_raw_cksum(&psd_hdr, sizeof(psd_hdr));
 }
@@ -319,8 +322,8 @@ rte_ipv4_phdr_cksum(const struct rte_ipv4_hdr *ipv4_hdr, uint64_t ol_flags)
 /**
  * Process the IPv4 UDP or TCP checksum.
  *
- * The IPv4 header should not contains options. The IP and layer 4
- * checksum must be set to 0 in the packet by the caller.
+ * The IP and layer 4 checksum must be set to 0 in the packet by
+ * the caller.
  *
  * @param ipv4_hdr
  *   The pointer to the contiguous IPv4 header.
@@ -334,12 +337,14 @@ rte_ipv4_udptcp_cksum(const struct rte_ipv4_hdr *ipv4_hdr, const void *l4_hdr)
 {
 	uint32_t cksum;
 	uint32_t l3_len, l4_len;
+	uint8_t ip_hdr_len;
 
+	ip_hdr_len = (ipv4_hdr->version_ihl & 0xf) * 4;
 	l3_len = rte_be_to_cpu_16(ipv4_hdr->total_length);
-	if (l3_len < sizeof(struct rte_ipv4_hdr))
+	if (l3_len < ip_hdr_len)
 		return 0;
 
-	l4_len = l3_len - sizeof(struct rte_ipv4_hdr);
+	l4_len = l3_len - ip_hdr_len;
 
 	cksum = rte_raw_cksum(l4_hdr, l4_len);
 	cksum += rte_ipv4_phdr_cksum(ipv4_hdr, 0);