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| author | Alin Nastac <alin.nastac@gmail.com> | 2019-10-08 12:54:11 +0200 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2019-10-09 12:14:23 +0200 |
| commit | bd7b0115c11870d3a97b8c0ed25498b6eed2aa8f (patch) | |
| tree | 77c18fa2011241fe1aa94568e34a9f456767abec | |
| parent | 62fb3c7201157026956255228392d0c52e1e294e (diff) | |
On big endian arches UDP/TCP checksum is incorrectly computed when
payload length is odd.
Signed-off-by: Alin Nastac <alin.nastac@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
| -rw-r--r-- | src/extra/checksum.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/src/extra/checksum.c b/src/extra/checksum.c index 4d52a99..42389aa 100644 --- 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 nfq_checksum(uint32_t sum, uint16_t *buf, int size) 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); |