slirp: Adding IPv6, ICMPv6 Echo and NDP autoconfiguration

This patch adds the functions needed to handle IPv6 packets. ICMPv6 and
NDP headers are implemented.

Slirp is now able to send NDP Router or Neighbor Advertisement when it
receives Router or Neighbor Solicitation. Using a 64bit-sized IPv6
prefix, the guest is now able to perform stateless autoconfiguration
(SLAAC) and to compute its IPv6 address.

This patch adds an ndp_table, mainly inspired by arp_table, to keep an
NDP cache and manage network address resolution.
Slirp regularly sends NDP Neighbor Advertisement, as recommended by the
RFC, to make the guest refresh its route.

This also adds ip6_cksum() to compute ICMPv6 checksums using IPv6
pseudo-header.

Some #define ETH_* are moved upper in slirp.h to make them accessible to
other slirp/*.h

Signed-off-by: Guillaume Subiron <maethor@subiron.org>
Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>

1 files changed, 25 insertions, 0 deletions

diff --git a/slirp/cksum.c b/slirp/cksum.c
index bc0d017d24..2ad0e6540d 100644
--- a/slirp/cksum.c
+++ b/slirp/cksum.c
@@ -138,3 +138,28 @@ cont:
 	REDUCE;
 	return (~sum & 0xffff);
 }
+
+int ip6_cksum(struct mbuf *m)
+{
+    /* TODO: Optimize this by being able to pass the ip6_pseudohdr to cksum
+     * separately from the mbuf */
+    struct ip6 save_ip, *ip = mtod(m, struct ip6 *);
+    struct ip6_pseudohdr *ih = mtod(m, struct ip6_pseudohdr *);
+    int sum;
+
+    save_ip = *ip;
+
+    ih->ih_src = save_ip.ip_src;
+    ih->ih_dst = save_ip.ip_dst;
+    ih->ih_pl = htonl((uint32_t)ntohs(save_ip.ip_pl));
+    ih->ih_zero_hi = 0;
+    ih->ih_zero_lo = 0;
+    ih->ih_nh = save_ip.ip_nh;
+
+    sum = cksum(m, ((int)sizeof(struct ip6_pseudohdr))
+                    + ntohl(ih->ih_pl));
+
+    *ip = save_ip;
+
+    return sum;
+}