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Add helpers for normal inbound packet destination addresses

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tap_ip_send() doesn't take a destination address, because it's specifically
for inbound packets, and the IP addresses of the guest/namespace are
already known to us.  Rather than open-coding this destination address
logic, make helper functions for it which will enable some later cleanups.

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 2022-10-19 11:43:49 +11:00 committed by Stefano Brivio
parent 3d8ccb44a6
commit a2eb2d310a
2 changed files with 31 additions and 5 deletions
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33
tap.c
View file

@ -96,6 +96,32 @@ int tap_send(const struct ctx *c, const void *data, size_t len, int vnet_pre)
return write(c->fd_tap, (char *)data + (vnet_pre ? 4 : 0), len); return write(c->fd_tap, (char *)data + (vnet_pre ? 4 : 0), len);
} }
/**
* tap_ip4_daddr() - Normal IPv4 destination address for inbound packets
* @c: Execution context
*
* Returns: IPv4 address, network order
*/
in_addr_t tap_ip4_daddr(const struct ctx *c)
{
return c->ip4.addr_seen;
}
/**
* tap_ip6_daddr() - Normal IPv4 destination address for inbound packets
* @c: Execution context
* @src: Source address
*
* Returns: pointer to IPv6 address
*/
const struct in6_addr *tap_ip6_daddr(const struct ctx *c,
const struct in6_addr *src)
{
if (IN6_IS_ADDR_LINKLOCAL(src))
return &c->ip6.addr_ll_seen;
return &c->ip6.addr_seen;
}
/** /**
* tap_ip_send() - Send IP packet, with L2 headers, calculating L3/L4 checksums * tap_ip_send() - Send IP packet, with L2 headers, calculating L3/L4 checksums
* @c: Execution context * @c: Execution context
@ -132,7 +158,7 @@ void tap_ip_send(const struct ctx *c, const struct in6_addr *src, uint8_t proto,
iph->frag_off = 0; iph->frag_off = 0;
iph->ttl = 255; iph->ttl = 255;
iph->protocol = proto; iph->protocol = proto;
iph->daddr = c->ip4.addr_seen; iph->daddr = tap_ip4_daddr(c);
memcpy(&iph->saddr, &src->s6_addr[12], 4); memcpy(&iph->saddr, &src->s6_addr[12], 4);
csum_ip4_header(iph); csum_ip4_header(iph);
@ -163,10 +189,7 @@ void tap_ip_send(const struct ctx *c, const struct in6_addr *src, uint8_t proto,
ip6h->priority = 0; ip6h->priority = 0;
ip6h->saddr = *src; ip6h->saddr = *src;
if (IN6_IS_ADDR_LINKLOCAL(src)) ip6h->daddr = *tap_ip6_daddr(c, src);
ip6h->daddr = c->ip6.addr_ll_seen;
else
ip6h->daddr = c->ip6.addr_seen;
memcpy(data, in, len); memcpy(data, in, len);

3
tap.h
View file

@ -6,6 +6,9 @@
#ifndef TAP_H #ifndef TAP_H
#define TAP_H #define TAP_H
in_addr_t tap_ip4_daddr(const struct ctx *c);
const struct in6_addr *tap_ip6_daddr(const struct ctx *c,
const struct in6_addr *src);
void tap_ip_send(const struct ctx *c, const struct in6_addr *src, uint8_t proto, void tap_ip_send(const struct ctx *c, const struct in6_addr *src, uint8_t proto,
const char *in, size_t len, uint32_t flow); const char *in, size_t len, uint32_t flow);
int tap_send(const struct ctx *c, const void *data, size_t len, int vnet_pre); int tap_send(const struct ctx *c, const void *data, size_t len, int vnet_pre);