We can find the same function to compute the IPv4 header
checksum in tcp.c, udp.c and tap.c
Use the function defined for tap.c, csum_ip4_header(), but
with the code used in tcp.c and udp.c as it doesn't need a fully
initialiazed IPv4 header, only protocol, tot_len, saddr and daddr.
Signed-off-by: Laurent Vivier <lvivier(a)redhat.com>
---
Notes:
v2:
- use csum_ip4_header() from checksum.c
- use code from tcp.c and udp.c in csum_ip4_header()
- use "const struct iphfr *", check is not updated by the
function but by the caller.
checksum.c | 16 ++++++++++++----
checksum.h | 2 +-
tap.c | 2 +-
tcp.c | 22 +---------------------
udp.c | 23 +++++------------------
5 files changed, 20 insertions(+), 45 deletions(-)
diff --git a/checksum.c b/checksum.c
index ac2bc49f7eb0..5613187a1c82 100644
--- a/checksum.c
+++ b/checksum.c
@@ -57,6 +57,7 @@
#include <linux/icmpv6.h>
#include "util.h"
+#include "ip.h"
/* Checksums are optional for UDP over IPv4, so we usually just set
* them to 0. Change this to 1 to calculate real UDP over IPv4
@@ -115,13 +116,20 @@ uint16_t csum_fold(uint32_t sum)
uint16_t csum(const void *buf, size_t len, uint32_t init);
/**
- * csum_ip4_header() - Calculate and set IPv4 header checksum
+ * csum_ip4_header() - Calculate IPv4 header checksum
* @ip4h: IPv4 header
*/
-void csum_ip4_header(struct iphdr *ip4h)
+uint16_t csum_ip4_header(const struct iphdr *ip4h)
{
- ip4h->check = 0;
- ip4h->check = csum(ip4h, (size_t)ip4h->ihl * 4, 0);
+ uint32_t sum = L2_BUF_IP4_PSUM(ip4h->protocol);
+
+ sum += ip4h->tot_len;
+ sum += (ip4h->saddr >> 16) & 0xffff;
+ sum += ip4h->saddr & 0xffff;
+ sum += (ip4h->daddr >> 16) & 0xffff;
+ sum += ip4h->daddr & 0xffff;
+
+ return ~csum_fold(sum);
}
/**
diff --git a/checksum.h b/checksum.h
index 6a20297a5826..b87ecd720df5 100644
--- a/checksum.h
+++ b/checksum.h
@@ -13,7 +13,7 @@ struct icmp6hdr;
uint32_t sum_16b(const void *buf, size_t len);
uint16_t csum_fold(uint32_t sum);
uint16_t csum_unaligned(const void *buf, size_t len, uint32_t init);
-void csum_ip4_header(struct iphdr *ip4h);
+uint16_t csum_ip4_header(const struct iphdr *ip4h);
void csum_udp4(struct udphdr *udp4hr,
struct in_addr saddr, struct in_addr daddr,
const void *payload, size_t len);
diff --git a/tap.c b/tap.c
index 3ea03f720d6d..70f36a55314f 100644
--- a/tap.c
+++ b/tap.c
@@ -160,7 +160,7 @@ static void *tap_push_ip4h(char *buf, struct in_addr src, struct
in_addr dst,
ip4h->protocol = proto;
ip4h->saddr = src.s_addr;
ip4h->daddr = dst.s_addr;
- csum_ip4_header(ip4h);
+ ip4h->check = csum_ip4_header(ip4h);
return ip4h + 1;
}
diff --git a/tcp.c b/tcp.c
index 45ef5146729a..35e240f4ffc3 100644
--- a/tcp.c
+++ b/tcp.c
@@ -934,23 +934,6 @@ static void tcp_sock_set_bufsize(const struct ctx *c, int s)
trace("TCP: failed to set SO_SNDBUF to %i", v);
}
-/**
- * tcp_update_check_ip4() - Update IPv4 with variable parts from stored one
- * @buf: L2 packet buffer with final IPv4 header
- */
-static void tcp_update_check_ip4(struct tcp4_l2_buf_t *buf)
-{
- uint32_t sum = L2_BUF_IP4_PSUM(IPPROTO_TCP);
-
- sum += buf->iph.tot_len;
- sum += (buf->iph.saddr >> 16) & 0xffff;
- sum += buf->iph.saddr & 0xffff;
- sum += (buf->iph.daddr >> 16) & 0xffff;
- sum += buf->iph.daddr & 0xffff;
-
- buf->iph.check = (uint16_t)~csum_fold(sum);
-}
-
/**
* tcp_update_check_tcp4() - Update TCP checksum from stored one
* @buf: L2 packet buffer with final IPv4 header
@@ -1393,10 +1376,7 @@ do { \
b->iph.saddr = a4->s_addr;
b->iph.daddr = c->ip4.addr_seen.s_addr;
- if (check)
- b->iph.check = *check;
- else
- tcp_update_check_ip4(b);
+ b->iph.check = check ? *check : csum_ip4_header(&b->iph);
SET_TCP_HEADER_COMMON_V4_V6(b, conn, seq);
diff --git a/udp.c b/udp.c
index d514c864ab5b..e645c800a823 100644
--- a/udp.c
+++ b/udp.c
@@ -270,23 +270,6 @@ static void udp_invert_portmap(struct udp_port_fwd *fwd)
}
}
-/**
- * udp_update_check4() - Update checksum with variable parts from stored one
- * @buf: L2 packet buffer with final IPv4 header
- */
-static void udp_update_check4(struct udp4_l2_buf_t *buf)
-{
- uint32_t sum = L2_BUF_IP4_PSUM(IPPROTO_UDP);
-
- sum += buf->iph.tot_len;
- sum += (buf->iph.saddr >> 16) & 0xffff;
- sum += buf->iph.saddr & 0xffff;
- sum += (buf->iph.daddr >> 16) & 0xffff;
- sum += buf->iph.daddr & 0xffff;
-
- buf->iph.check = (uint16_t)~csum_fold(sum);
-}
-
/**
* udp_update_l2_buf() - Update L2 buffers with Ethernet and IPv4 addresses
* @eth_d: Ethernet destination address, NULL if unchanged
@@ -579,6 +562,9 @@ static void udp_splice_sendfrom(const struct ctx *c, unsigned start,
unsigned n,
*
* Return: size of tap frame with headers
*/
+#pragma GCC diagnostic push
+/* ignore unaligned pointer value warning for &b->iph */
+#pragma GCC diagnostic ignored "-Waddress-of-packed-member"
static size_t udp_update_hdr4(const struct ctx *c, int n, in_port_t dstport,
const struct timespec *now)
{
@@ -614,13 +600,14 @@ static size_t udp_update_hdr4(const struct ctx *c, int n, in_port_t
dstport,
b->iph.saddr = b->s_in.sin_addr.s_addr;
}
- udp_update_check4(b);
+ b->iph.check = csum_ip4_header(&b->iph);
b->uh.source = b->s_in.sin_port;
b->uh.dest = htons(dstport);
b->uh.len = htons(udp4_l2_mh_sock[n].msg_len + sizeof(b->uh));
return tap_iov_len(c, &b->taph, ip_len);
}
+#pragma GCC diagnostic pop
/**
* udp_update_hdr6() - Update headers for one IPv6 datagram
--
2.42.0