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libnetfilter_queue: fix checksum computation

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There are 2 issues fixed by this patch:
  - UDP checksum is computed incorrectly, the used pseudo IP header
    contains transport protocol 6 iso 17
  - on big endian arches the UDP/TCP checksum is incorrectly
    computed when payload length is odd

Signed-off-by: Alin Nastac <alin.nastac@gmail.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name> [refresh patch]
This commit is contained in:
Alin Năstac 2016-06-24 14:41:10 +02:00 committed by Felix Fietkau
parent e6b9330343
commit 86a2702a00
1 changed files with 113 additions and 0 deletions
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113
package/libs/libnetfilter-queue/patches/100-checksum_computation.patch Normal file
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@ -0,0 +1,113 @@
--- a/src/extra/checksum.c
+++ b/src/extra/checksum.c
@@ -11,6 +11,7 @@
#include <stdio.h>
#include <stdbool.h>
+#include <endian.h>
#include <arpa/inet.h>
#include <netinet/ip.h>
#include <netinet/ip6.h>
@@ -26,8 +27,13 @@ uint16_t checksum(uint32_t sum, uint16_t
sum += *buf++;
size -= sizeof(uint16_t);
}
- if (size)
- sum += *(uint8_t *)buf;
+ if (size) {
+#if __BYTE_ORDER == __BIG_ENDIAN
+ sum += (uint16_t)*(uint8_t *)buf << 8;
+#else
+ sum += (uint16_t)*(uint8_t *)buf;
+#endif
+ }
sum = (sum >> 16) + (sum & 0xffff);
sum += (sum >>16);
@@ -35,7 +41,7 @@ uint16_t checksum(uint32_t sum, uint16_t
return (uint16_t)(~sum);
}
-uint16_t checksum_tcpudp_ipv4(struct iphdr *iph)
+uint16_t checksum_tcpudp_ipv4(struct iphdr *iph, uint16_t protocol_id)
{
uint32_t sum = 0;
uint32_t iph_len = iph->ihl*4;
@@ -46,13 +52,13 @@ uint16_t checksum_tcpudp_ipv4(struct iph
sum += (iph->saddr) & 0xFFFF;
sum += (iph->daddr >> 16) & 0xFFFF;
sum += (iph->daddr) & 0xFFFF;
- sum += htons(IPPROTO_TCP);
+ sum += htons(protocol_id);
sum += htons(len);
return checksum(sum, (uint16_t *)payload, len);
}
-uint16_t checksum_tcpudp_ipv6(struct ip6_hdr *ip6h, void *transport_hdr)
+uint16_t checksum_tcpudp_ipv6(struct ip6_hdr *ip6h, void *transport_hdr, uint16_t protocol_id)
{
uint32_t sum = 0;
uint32_t hdr_len = (uint32_t *)transport_hdr - (uint32_t *)ip6h;
@@ -68,7 +74,7 @@ uint16_t checksum_tcpudp_ipv6(struct ip6
sum += (ip6h->ip6_dst.s6_addr16[i] >> 16) & 0xFFFF;
sum += (ip6h->ip6_dst.s6_addr16[i]) & 0xFFFF;
}
- sum += htons(IPPROTO_TCP);
+ sum += htons(protocol_id);
sum += htons(ip6h->ip6_plen);
return checksum(sum, (uint16_t *)payload, len);
--- a/src/extra/tcp.c
+++ b/src/extra/tcp.c
@@ -91,7 +91,7 @@ nfq_tcp_compute_checksum_ipv4(struct tcp
{
/* checksum field in header needs to be zero for calculation. */
tcph->check = 0;
- tcph->check = checksum_tcpudp_ipv4(iph);
+ tcph->check = checksum_tcpudp_ipv4(iph, IPPROTO_TCP);
}
EXPORT_SYMBOL(nfq_tcp_compute_checksum_ipv4);
@@ -105,7 +105,7 @@ nfq_tcp_compute_checksum_ipv6(struct tcp
{
/* checksum field in header needs to be zero for calculation. */
tcph->check = 0;
- tcph->check = checksum_tcpudp_ipv6(ip6h, tcph);
+ tcph->check = checksum_tcpudp_ipv6(ip6h, tcph, IPPROTO_TCP);
}
EXPORT_SYMBOL(nfq_tcp_compute_checksum_ipv6);
--- a/src/extra/udp.c
+++ b/src/extra/udp.c
@@ -91,7 +91,7 @@ nfq_udp_compute_checksum_ipv4(struct udp
{
/* checksum field in header needs to be zero for calculation. */
udph->check = 0;
- udph->check = checksum_tcpudp_ipv4(iph);
+ udph->check = checksum_tcpudp_ipv4(iph, IPPROTO_UDP);
}
EXPORT_SYMBOL(nfq_udp_compute_checksum_ipv4);
@@ -110,7 +110,7 @@ nfq_udp_compute_checksum_ipv6(struct udp
{
/* checksum field in header needs to be zero for calculation. */
udph->check = 0;
- udph->check = checksum_tcpudp_ipv6(ip6h, udph);
+ udph->check = checksum_tcpudp_ipv6(ip6h, udph, IPPROTO_UDP);
}
EXPORT_SYMBOL(nfq_udp_compute_checksum_ipv6);
--- a/src/internal.h
+++ b/src/internal.h
@@ -13,8 +13,8 @@ struct iphdr;
struct ip6_hdr;
uint16_t checksum(uint32_t sum, uint16_t *buf, int size);
-uint16_t checksum_tcpudp_ipv4(struct iphdr *iph);
-uint16_t checksum_tcpudp_ipv6(struct ip6_hdr *ip6h, void *transport_hdr);
+uint16_t checksum_tcpudp_ipv4(struct iphdr *iph, uint16_t protocol_id);
+uint16_t checksum_tcpudp_ipv6(struct ip6_hdr *ip6h, void *transport_hdr, uint16_t protocol_id);
struct pkt_buff {
uint8_t *mac_header;