net: qualcomm: rmnet: trailer value is a checksum

The csum_value field in the rmnet_map_dl_csum_trailer structure is a
"real" Internet checksum.  It is a 16 bit value, in big endian format,
which represents an inverted ones' complement sum over pairs of bytes.

Make that clear by changing its type to __sum16.

This makes a typecast in rmnet_map_ipv4_dl_csum_trailer() and
another in rmnet_map_ipv6_dl_csum_trailer() unnecessary.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Alex Elder 2021-06-12 09:37:34 -05:00 committed by David S. Miller
parent 698aa6c46b
commit be754f6435
2 changed files with 3 additions and 4 deletions

View File

@ -87,7 +87,7 @@ rmnet_map_ipv4_dl_csum_trailer(struct sk_buff *skb,
* header checksum value; it is already accounted for in the
* checksum value found in the trailer.
*/
ip_payload_csum = (__force __sum16)~csum_trailer->csum_value;
ip_payload_csum = ~csum_trailer->csum_value;
pseudo_csum = ~csum_tcpudp_magic(ip4h->saddr, ip4h->daddr,
ntohs(ip4h->tot_len) - ip4h->ihl * 4,
@ -132,8 +132,7 @@ rmnet_map_ipv6_dl_csum_trailer(struct sk_buff *skb,
* checksum computed over the pseudo header.
*/
ip_header_csum = (__force __be16)ip_fast_csum(ip6h, sizeof(*ip6h) / 4);
ip6_payload_csum = ~csum16_sub((__force __sum16)csum_trailer->csum_value,
ip_header_csum);
ip6_payload_csum = ~csum16_sub(csum_trailer->csum_value, ip_header_csum);
length = (ip6h->nexthdr == IPPROTO_UDP) ?
ntohs(((struct udphdr *)txporthdr)->len) :

View File

@ -25,7 +25,7 @@ struct rmnet_map_dl_csum_trailer {
u8 flags; /* MAP_CSUM_DL_VALID_FLAG */
__be16 csum_start_offset;
__be16 csum_length;
__be16 csum_value;
__sum16 csum_value;
} __aligned(1);
/* rmnet_map_dl_csum_trailer flags field: