On Mon, 17 Oct 2022 19:57:59 +1100 David Gibson <david(a)gibson.dropbear.id.au> wrote: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(a)gibson.dropbear.id.au> --- tap.c | 29 ++++++++++++++++++++++++----- tap.h | 3 +++ 2 files changed, 27 insertions(+), 5 deletions(-) diff --git a/tap.c b/tap.c index de02c56..41e8ff2 100644 --- a/tap.c +++ b/tap.c @@ -96,6 +96,28 @@ 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); } +/** + * tap_ip4_daddr() - Normal IPv4 destination address for inbound packets + * @c: Execution contextGiven that the address is returned in network order, I think this would be relevant here: * Return: 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* Return: 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 * @c: Execution context @@ -132,7 +154,7 @@ void tap_ip_send(const struct ctx *c, const struct in6_addr *src, uint8_t proto, iph->frag_off = 0; iph->ttl = 255; iph->protocol = proto; - iph->daddr = c->ip4.addr_seen; + iph->daddr = tap_ip4_daddr(c); memcpy(&iph->saddr, &src->s6_addr[12], 4); csum_ip4_header(iph); @@ -163,10 +185,7 @@ void tap_ip_send(const struct ctx *c, const struct in6_addr *src, uint8_t proto, ip6h->priority = 0; ip6h->saddr = *src; - if (IN6_IS_ADDR_LINKLOCAL(src)) - ip6h->daddr = c->ip6.addr_ll_seen; - else - ip6h->daddr = c->ip6.addr_seen; + ip6h->daddr = *tap_ip6_daddr(c, src); memcpy(data, in, len); diff --git a/tap.h b/tap.h index df3aec0..a6764b4 100644 --- a/tap.h +++ b/tap.h @@ -6,6 +6,9 @@ #ifndef 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, 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);-- Stefano