udp: Update UDP checksum using an iovec array

As for tcp_update_check_tcp4()/tcp_update_check_tcp6(),
change csum_udp4() and csum_udp6() to use an iovec array.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>

5 files changed, 45 insertions, 21 deletions

diff --git a/checksum.c b/checksum.c
index cf85019..c673993 100644
--- a/checksum.c
+++ b/checksum.c
@@ -166,22 +166,24 @@ uint32_t proto_ipv4_header_psum(uint16_t l4len, uint8_t protocol,
  * @udp4hr:	UDP header, initialised apart from checksum
  * @saddr:	IPv4 source address
  * @daddr:	IPv4 destination address
- * @payload:	UDP packet payload
- * @dlen:	Length of @payload (not including UDP header)
+ * @iov:	Pointer to the array of IO vectors
+ * @iov_cnt:	Length of the array
+ * @offset:	UDP payload offset in the iovec array
  */
 void csum_udp4(struct udphdr *udp4hr,
 	       struct in_addr saddr, struct in_addr daddr,
-	       const void *payload, size_t dlen)
+	       const struct iovec *iov, int iov_cnt, size_t offset)
 {
 	/* UDP checksums are optional, so don't bother */
 	udp4hr->check = 0;
 
 	if (UDP4_REAL_CHECKSUMS) {
-		uint16_t l4len = dlen + sizeof(struct udphdr);
+		uint16_t l4len = iov_size(iov, iov_cnt) - offset +
+				 sizeof(struct udphdr);
 		uint32_t psum = proto_ipv4_header_psum(l4len, IPPROTO_UDP,
 						       saddr, daddr);
 		psum = csum_unfolded(udp4hr, sizeof(struct udphdr), psum);
-		udp4hr->check = csum(payload, dlen, psum);
+		udp4hr->check = csum_iov(iov, iov_cnt, offset, psum);
 	}
 }
 
@@ -227,19 +229,24 @@ uint32_t proto_ipv6_header_psum(uint16_t payload_len, uint8_t protocol,
 /**
  * csum_udp6() - Calculate and set checksum for a UDP over IPv6 packet
  * @udp6hr:	UDP header, initialised apart from checksum
- * @payload:	UDP packet payload
- * @dlen:	Length of @payload (not including UDP header)
+ * @saddr:	Source address
+ * @daddr:	Destination address
+ * @iov:	Pointer to the array of IO vectors
+ * @iov_cnt:	Length of the array
+ * @offset:	UDP payload offset in the iovec array
  */
 void csum_udp6(struct udphdr *udp6hr,
 	       const struct in6_addr *saddr, const struct in6_addr *daddr,
-	       const void *payload, size_t dlen)
+	       const struct iovec *iov, int iov_cnt, size_t offset)
 {
-	uint32_t psum = proto_ipv6_header_psum(dlen + sizeof(struct udphdr),
-					       IPPROTO_UDP, saddr, daddr);
+	uint16_t l4len = iov_size(iov, iov_cnt) - offset +
+			 sizeof(struct udphdr);
+	uint32_t psum = proto_ipv6_header_psum(l4len, IPPROTO_UDP,
+					       saddr, daddr);
 	udp6hr->check = 0;
 
 	psum = csum_unfolded(udp6hr, sizeof(struct udphdr), psum);
-	udp6hr->check = csum(payload, dlen, psum);
+	udp6hr->check = csum_iov(iov, iov_cnt, offset, psum);
 }
 
 /**
diff --git a/checksum.h b/checksum.h
index 49f7472..31ba322 100644
--- a/checksum.h
+++ b/checksum.h
@@ -19,14 +19,14 @@ uint32_t proto_ipv4_header_psum(uint16_t l4len, uint8_t protocol,
 				struct in_addr saddr, struct in_addr daddr);
 void csum_udp4(struct udphdr *udp4hr,
 	       struct in_addr saddr, struct in_addr daddr,
-	       const void *payload, size_t dlen);
+	       const struct iovec *iov, int iov_cnt, size_t offset);
 void csum_icmp4(struct icmphdr *icmp4hr, const void *payload, size_t dlen);
 uint32_t proto_ipv6_header_psum(uint16_t payload_len, uint8_t protocol,
 				const struct in6_addr *saddr,
 				const struct in6_addr *daddr);
 void csum_udp6(struct udphdr *udp6hr,
 	       const struct in6_addr *saddr, const struct in6_addr *daddr,
-	       const void *payload, size_t dlen);
+	       const struct iovec *iov, int iov_cnt, size_t offset);
 void csum_icmp6(struct icmp6hdr *icmp6hr,
 		const struct in6_addr *saddr, const struct in6_addr *daddr,
 		const void *payload, size_t dlen);
diff --git a/tap.c b/tap.c
index 41af6a6..c53a39b 100644
--- a/tap.c
+++ b/tap.c
@@ -172,11 +172,15 @@ void tap_udp4_send(const struct ctx *c, struct in_addr src, in_port_t sport,
 	struct iphdr *ip4h = tap_push_l2h(c, buf, ETH_P_IP);
 	struct udphdr *uh = tap_push_ip4h(ip4h, src, dst, l4len, IPPROTO_UDP);
 	char *data = (char *)(uh + 1);
+	const struct iovec iov = {
+		.iov_base = (void *)in,
+		.iov_len = dlen
+	};
 
 	uh->source = htons(sport);
 	uh->dest = htons(dport);
 	uh->len = htons(l4len);
-	csum_udp4(uh, src, dst, in, dlen);
+	csum_udp4(uh, src, dst, &iov, 1, 0);
 	memcpy(data, in, dlen);
 
 	tap_send_single(c, buf, dlen + (data - buf));
@@ -247,7 +251,7 @@ static void *tap_push_ip6h(struct ipv6hdr *ip6h,
 void tap_udp6_send(const struct ctx *c,
 		   const struct in6_addr *src, in_port_t sport,
 		   const struct in6_addr *dst, in_port_t dport,
-		   uint32_t flow, const void *in, size_t dlen)
+		   uint32_t flow, void *in, size_t dlen)
 {
 	size_t l4len = dlen + sizeof(struct udphdr);
 	char buf[USHRT_MAX];
@@ -255,11 +259,15 @@ void tap_udp6_send(const struct ctx *c,
 	struct udphdr *uh = tap_push_ip6h(ip6h, src, dst,
 					  l4len, IPPROTO_UDP, flow);
 	char *data = (char *)(uh + 1);
+	const struct iovec iov = {
+		.iov_base = in,
+		.iov_len = dlen
+	};
 
 	uh->source = htons(sport);
 	uh->dest = htons(dport);
 	uh->len = htons(l4len);
-	csum_udp6(uh, src, dst, in, dlen);
+	csum_udp6(uh, src, dst, &iov, 1, 0);
 	memcpy(data, in, dlen);
 
 	tap_send_single(c, buf, dlen + (data - buf));
diff --git a/tap.h b/tap.h
index ec9e2ac..85f1e84 100644
--- a/tap.h
+++ b/tap.h
@@ -53,7 +53,7 @@ const struct in6_addr *tap_ip6_daddr(const struct ctx *c,
 void tap_udp6_send(const struct ctx *c,
 		   const struct in6_addr *src, in_port_t sport,
 		   const struct in6_addr *dst, in_port_t dport,
-		   uint32_t flow, const void *in, size_t dlen);
+		   uint32_t flow, void *in, size_t dlen);
 void tap_icmp6_send(const struct ctx *c,
 		    const struct in6_addr *src, const struct in6_addr *dst,
 		    const void *in, size_t l4len);
diff --git a/udp.c b/udp.c
index 08faaec..100610f 100644
--- a/udp.c
+++ b/udp.c
@@ -321,10 +321,15 @@ static size_t udp_update_hdr4(struct iphdr *ip4h, struct udp_payload_t *bp,
 	bp->uh.source = htons(toside->oport);
 	bp->uh.dest = htons(toside->eport);
 	bp->uh.len = htons(l4len);
-	if (no_udp_csum)
+	if (no_udp_csum) {
 		bp->uh.check = 0;
-	else
-		csum_udp4(&bp->uh, *src, *dst, bp->data, dlen);
+	} else {
+		const struct iovec iov = {
+			.iov_base = bp->data,
+			.iov_len = dlen
+		};
+		csum_udp4(&bp->uh, *src, *dst, &iov, 1, 0);
+	}
 
 	return l4len;
 }
@@ -363,8 +368,12 @@ static size_t udp_update_hdr6(struct ipv6hdr *ip6h, struct udp_payload_t *bp,
 		 */
 		bp->uh.check = 0xffff;
 	} else {
+		const struct iovec iov = {
+			.iov_base = bp->data,
+			.iov_len = dlen
+		};
 		csum_udp6(&bp->uh, &toside->oaddr.a6, &toside->eaddr.a6,
-			  bp->data, dlen);
+			  &iov, 1, 0);
 	}
 
 	return l4len;