External/passt
1
0
Fork 0
mirror of https://passt.top/passt synced 2024-12-21 21:25:23 +00:00
Code Issues Packages Projects Releases Wiki Activity

iov, checksum: Replace csum_iov() with csum_iov_tail()

Browse Source 
We usually want to checksum only the tail part of a frame, excluding at
least some headers.  csum_iov() does that for a frame represented as an
IO vector, not actually summing the entire IO vector.  We now have struct
iov_tail to explicitly represent this construct, so replace csum_iov()
with csum_iov_tail() taking that representation rather than 3 parameters.

We propagate the same change to csum_udp4() and csum_udp6() which take
similar parameters.  This slightly simplifies the code, and will allow some
further simplifications as struct iov_tail is more widely used.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
David Gibson 2024-11-27 14:54:05 +11:00 committed by Stefano Brivio
parent f931103171
commit 67151090bc
7 changed files with 43 additions and 50 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

56
checksum.c
View File

@ -166,24 +166,22 @@ 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
* @iov: Pointer to the array of IO vectors
* @iov_cnt: Length of the array
* @offset: UDP payload offset in the iovec array
* @data: UDP payload (as IO vector tail)
*/
void csum_udp4(struct udphdr *udp4hr,
struct in_addr saddr, struct in_addr daddr,
const struct iovec *iov, int iov_cnt, size_t offset)
struct iov_tail *data)
{
/* UDP checksums are optional, so don't bother */
udp4hr->check = 0;
if (UDP4_REAL_CHECKSUMS) {
uint16_t l4len = iov_size(iov, iov_cnt) - offset +
sizeof(struct udphdr);
uint16_t l4len = iov_tail_size(data) + 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_iov(iov, iov_cnt, offset, psum);
udp4hr->check = csum_iov_tail(data, psum);
}
}
@ -231,22 +229,20 @@ uint32_t proto_ipv6_header_psum(uint16_t payload_len, uint8_t protocol,
* @udp6hr: UDP header, initialised apart from checksum
* @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
* @data: UDP payload (as IO vector tail)
*/
void csum_udp6(struct udphdr *udp6hr,
const struct in6_addr *saddr, const struct in6_addr *daddr,
const struct iovec *iov, int iov_cnt, size_t offset)
struct iov_tail *data)
{
uint16_t l4len = iov_size(iov, iov_cnt) - offset +
sizeof(struct udphdr);
uint16_t l4len = iov_tail_size(data) + 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_iov(iov, iov_cnt, offset, psum);
udp6hr->check = csum_iov_tail(data, psum);
}
/**
@ -501,31 +497,23 @@ uint16_t csum(const void *buf, size_t len, uint32_t init)
}
/**
* csum_iov() - Calculates the unfolded checksum over an array of IO vectors
*
* @iov Pointer to the array of IO vectors
* @n Length of the array
* @offset: Offset of the data to checksum within the full data length
* csum_iov_tail() - Calculate unfolded checksum for the tail of an IO vector
* @tail: IO vector tail to checksum
* @init Initial 32-bit checksum, 0 for no pre-computed checksum
*
* Return: 16-bit folded, complemented checksum
*/
uint16_t csum_iov(const struct iovec *iov, size_t n, size_t offset,
uint32_t init)
uint16_t csum_iov_tail(struct iov_tail *tail, uint32_t init)
{
unsigned int i;
size_t first;
i = iov_skip_bytes(iov, n, offset, &first);
if (i >= n)
return (uint16_t)~csum_fold(init);
init = csum_unfolded((char *)iov[i].iov_base + first,
iov[i].iov_len - first, init);
i++;
for (; i < n; i++)
init = csum_unfolded(iov[i].iov_base, iov[i].iov_len, init);
if (iov_tail_prune(tail)) {
size_t i;
init = csum_unfolded((char *)tail->iov[0].iov_base + tail->off,
tail->iov[0].iov_len - tail->off, init);
for (i = 1; i < tail->cnt; i++) {
const struct iovec *iov = &tail->iov[i];
init = csum_unfolded(iov->iov_base, iov->iov_len, init);
}
}
return (uint16_t)~csum_fold(init);
}

8
checksum.h
View File

@ -9,6 +9,7 @@
struct udphdr;
struct icmphdr;
struct icmp6hdr;
struct iov_tail;
uint32_t sum_16b(const void *buf, size_t len);
uint16_t csum_fold(uint32_t sum);
@ -19,20 +20,19 @@ 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 struct iovec *iov, int iov_cnt, size_t offset);
struct iov_tail *data);
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 struct iovec *iov, int iov_cnt, size_t offset);
struct iov_tail *data);
void csum_icmp6(struct icmp6hdr *icmp6hr,
const struct in6_addr *saddr, const struct in6_addr *daddr,
const void *payload, size_t dlen);
uint32_t csum_unfolded(const void *buf, size_t len, uint32_t init);
uint16_t csum(const void *buf, size_t len, uint32_t init);
uint16_t csum_iov(const struct iovec *iov, size_t n, size_t offset,
uint32_t init);
uint16_t csum_iov_tail(struct iov_tail *tail, uint32_t init);
#endif /* CHECKSUM_H */

1
iov.c
View File

@ -185,7 +185,6 @@ bool iov_tail_prune(struct iov_tail *tail)
*
* Returns: The total size in bytes.
*/
/* cppcheck-suppress unusedFunction */
size_t iov_tail_size(struct iov_tail *tail)
{
iov_tail_prune(tail);

6
tap.c
View File

@ -184,11 +184,12 @@ void tap_udp4_send(const struct ctx *c, struct in_addr src, in_port_t sport,
.iov_base = (void *)in,
.iov_len = dlen
};
struct iov_tail payload = IOV_TAIL(&iov, 1, 0);
uh->source = htons(sport);
uh->dest = htons(dport);
uh->len = htons(l4len);
csum_udp4(uh, src, dst, &iov, 1, 0);
csum_udp4(uh, src, dst, &payload);
memcpy(data, in, dlen);
tap_send_single(c, buf, dlen + (data - buf));
@ -271,11 +272,12 @@ void tap_udp6_send(const struct ctx *c,
.iov_base = in,
.iov_len = dlen
};
struct iov_tail payload = IOV_TAIL(&iov, 1, 0);
uh->source = htons(sport);
uh->dest = htons(dport);
uh->len = htons(l4len);
csum_udp6(uh, src, dst, &iov, 1, 0);
csum_udp6(uh, src, dst, &payload);
memcpy(data, in, dlen);
tap_send_single(c, buf, dlen + (data - buf));

6
tcp.c
View File

@ -764,6 +764,7 @@ void tcp_update_check_tcp4(const struct iphdr *iph,
size_t l4offset)
{
uint16_t l4len = ntohs(iph->tot_len) - sizeof(struct iphdr);
struct iov_tail l4 = IOV_TAIL(iov, iov_cnt, l4offset);
struct in_addr saddr = { .s_addr = iph->saddr };
struct in_addr daddr = { .s_addr = iph->daddr };
size_t check_ofs;
@ -801,7 +802,7 @@ void tcp_update_check_tcp4(const struct iphdr *iph,
check = (uint16_t *)ptr;
*check = 0;
*check = csum_iov(iov, iov_cnt, l4offset, sum);
*check = csum_iov_tail(&l4, sum);
}
/**
@ -815,6 +816,7 @@ void tcp_update_check_tcp6(const struct ipv6hdr *ip6h,
const struct iovec *iov, int iov_cnt,
size_t l4offset)
{
struct iov_tail l4 = IOV_TAIL(iov, iov_cnt, l4offset);
uint16_t l4len = ntohs(ip6h->payload_len);
size_t check_ofs;
uint16_t *check;
@ -852,7 +854,7 @@ void tcp_update_check_tcp6(const struct ipv6hdr *ip6h,
check = (uint16_t *)ptr;
*check = 0;
*check = csum_iov(iov, iov_cnt, l4offset, sum);
*check = csum_iov_tail(&l4, sum);
}
/**

7
udp.c
View File

@ -316,7 +316,8 @@ size_t udp_update_hdr4(struct iphdr *ip4h, struct udp_payload_t *bp,
.iov_base = bp->data,
.iov_len = dlen
};
csum_udp4(&bp->uh, *src, *dst, &iov, 1, 0);
struct iov_tail data = IOV_TAIL(&iov, 1, 0);
csum_udp4(&bp->uh, *src, *dst, &data);
}
return l4len;
@ -360,8 +361,8 @@ size_t udp_update_hdr6(struct ipv6hdr *ip6h, struct udp_payload_t *bp,
.iov_base = bp->data,
.iov_len = dlen
};
csum_udp6(&bp->uh, &toside->oaddr.a6, &toside->eaddr.a6,
&iov, 1, 0);
struct iov_tail data = IOV_TAIL(&iov, 1, 0);
csum_udp6(&bp->uh, &toside->oaddr.a6, &toside->eaddr.a6, &data);
}
return l4len;

9
udp_vu.c
View File

@ -199,15 +199,16 @@ static void udp_vu_csum(const struct flowside *toside, int iov_used)
const struct in_addr *dst4 = inany_v4(&toside->eaddr);
char *base = iov_vu[0].iov_base;
struct udp_payload_t *bp;
struct iov_tail data;
if (src4 && dst4) {
bp = vu_payloadv4(base);
csum_udp4(&bp->uh, *src4, *dst4, iov_vu, iov_used,
(char *)&bp->data - base);
data = IOV_TAIL(iov_vu, iov_used, (char *)&bp->data - base);
csum_udp4(&bp->uh, *src4, *dst4, &data);
} else {
bp = vu_payloadv6(base);
csum_udp6(&bp->uh, &toside->oaddr.a6, &toside->eaddr.a6,
iov_vu, iov_used, (char *)&bp->data - base);
data = IOV_TAIL(iov_vu, iov_used, (char *)&bp->data - base);
csum_udp6(&bp->uh, &toside->oaddr.a6, &toside->eaddr.a6, &data);
}
}