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tcp: Merge tcp_update_check_tcp[46]()

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The only reason we need separate functions for the IPv4 and IPv6 case is
to calculate the checksum of the IP pseudo-header, which is different for
the two cases.  However, the caller already knows which path it's on and
can access the values needed for the pseudo-header partial sum more easily
than tcp_update_check_tcp[46]() can.

So, merge these functions into a single tcp_update_csum() function that
just takes the pseudo-header partial sum, calculated in the caller.

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 14:54:08 +11:00 committed by Stefano Brivio
parent 08ea3cc581
commit 2abf5ab7f3
3 changed files with 36 additions and 51 deletions
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59
tcp.c
View File

@ -753,44 +753,16 @@ static void tcp_sock_set_bufsize(const struct ctx *c, int s)
}
/**
* tcp_update_check_tcp4() - Calculate TCP checksum for IPv4
* @iph: IPv4 header
* tcp_update_csum() - Calculate TCP checksum
* @psum: Unfolded partial checksum of the IPv4 or IPv6 pseudo-header
* @th: TCP header (updated)
* @payload: TCP payload
*/
void tcp_update_check_tcp4(const struct iphdr *iph, struct tcphdr *th,
struct iov_tail *payload)
void tcp_update_csum(uint32_t psum, struct tcphdr *th, struct iov_tail *payload)
{
uint16_t l4len = ntohs(iph->tot_len) - sizeof(struct iphdr);
struct in_addr saddr = { .s_addr = iph->saddr };
struct in_addr daddr = { .s_addr = iph->daddr };
uint32_t sum;
sum = proto_ipv4_header_psum(l4len, IPPROTO_TCP, saddr, daddr);
th->check = 0;
sum = csum_unfolded(th, sizeof(*th), sum);
th->check = csum_iov_tail(payload, sum);
}
/**
* tcp_update_check_tcp6() - Calculate TCP checksum for IPv6
* @ip6h: IPv6 header
* @th: TCP header (updated)
* @payload: TCP payload
*/
void tcp_update_check_tcp6(const struct ipv6hdr *ip6h, struct tcphdr *th,
struct iov_tail *payload)
{
uint16_t l4len = ntohs(ip6h->payload_len);
uint32_t sum;
sum = proto_ipv6_header_psum(l4len, IPPROTO_TCP, &ip6h->saddr,
&ip6h->daddr);
th->check = 0;
sum = csum_unfolded(th, sizeof(*th), sum);
th->check = csum_iov_tail(payload, sum);
psum = csum_unfolded(th, sizeof(*th), psum);
th->check = csum_iov_tail(payload, psum);
}
/**
@ -937,10 +909,14 @@ void tcp_fill_headers4(const struct tcp_tap_conn *conn,
tcp_fill_header(th, conn, seq);
if (no_tcp_csum)
if (no_tcp_csum) {
th->check = 0;
else
tcp_update_check_tcp4(iph, th, payload);
} else {
uint32_t psum = proto_ipv4_header_psum(l4len, IPPROTO_TCP,
*src4, *dst4);
tcp_update_csum(psum, th, payload);
}
tap_hdr_update(taph, l3len + sizeof(struct ethhdr));
}
@ -978,10 +954,15 @@ void tcp_fill_headers6(const struct tcp_tap_conn *conn,
tcp_fill_header(th, conn, seq);
if (no_tcp_csum)
if (no_tcp_csum) {
th->check = 0;
else
tcp_update_check_tcp6(ip6h, th, payload);
} else {
uint32_t psum = proto_ipv6_header_psum(l4len, IPPROTO_TCP,
&ip6h->saddr,
&ip6h->daddr);
tcp_update_csum(psum, th, payload);
}
tap_hdr_update(taph, l4len + sizeof(*ip6h) + sizeof(struct ethhdr));
}

6
tcp_internal.h
View File

@ -162,10 +162,8 @@ void tcp_rst_do(const struct ctx *c, struct tcp_tap_conn *conn);
struct tcp_info_linux;
void tcp_update_check_tcp4(const struct iphdr *iph, struct tcphdr *th,
struct iov_tail *payload);
void tcp_update_check_tcp6(const struct ipv6hdr *ip6h, struct tcphdr *th,
struct iov_tail *payload);
void tcp_update_csum(uint32_t psum, struct tcphdr *th,
struct iov_tail *payload);
void tcp_fill_headers4(const struct tcp_tap_conn *conn,
struct tap_hdr *taph, struct iphdr *iph,
struct tcphdr *th, struct iov_tail *payload,

22
tcp_vu.c
View File

@ -71,22 +71,28 @@ static void tcp_vu_update_check(const struct flowside *tapside,
struct iovec *iov, int iov_cnt)
{
char *base = iov[0].iov_base;
struct iov_tail payload;
struct tcphdr *th;
uint32_t psum;
if (inany_v4(&tapside->oaddr)) {
struct tcphdr *th = vu_payloadv4(base);
const struct in_addr *src4 = inany_v4(&tapside->oaddr);
const struct in_addr *dst4 = inany_v4(&tapside->eaddr);
const struct iphdr *iph = vu_ip(base);
struct iov_tail payload = IOV_TAIL(iov, iov_cnt,
(char *)(th + 1) - base);
size_t l4len = ntohs(iph->tot_len) - sizeof(*iph);
tcp_update_check_tcp4(iph, th, &payload);
th = vu_payloadv4(base);
psum = proto_ipv4_header_psum(l4len, IPPROTO_TCP, *src4, *dst4);
} else {
struct tcphdr *th = vu_payloadv6(base);
const struct ipv6hdr *ip6h = vu_ip(base);
struct iov_tail payload = IOV_TAIL(iov, iov_cnt,
(char *)(th + 1) - base);
size_t l4len = ntohs(ip6h->payload_len);
tcp_update_check_tcp6(ip6h, th, &payload);
th = vu_payloadv6(base);
psum = proto_ipv6_header_psum(l4len, IPPROTO_TCP,
&ip6h->saddr, &ip6h->daddr);
}
payload = IOV_TAIL(iov, iov_cnt, (char *)(th + 1) - base);
tcp_update_csum(psum, th, &payload);
}
/**