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, 90 insertions, 0 deletions

diff --git a/slirp/ndp_table.c b/slirp/ndp_table.c
new file mode 100644
index 0000000..9d4c39b
--- /dev/null
+++ b/slirp/ndp_table.c
@@ -0,0 +1,90 @@
+/*
+ * Copyright (c) 2013
+ * Guillaume Subiron, Yann Bordenave, Serigne Modou Wagne.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "slirp.h"
+
+void ndp_table_add(Slirp *slirp, struct in6_addr ip_addr,
+                    uint8_t ethaddr[ETH_ALEN])
+{
+    NdpTable *ndp_table = &slirp->ndp_table;
+    int i;
+
+    DEBUG_CALL("ndp_table_add");
+#if !defined(_WIN32) || (_WIN32_WINNT >= 0x0600)
+    char addrstr[INET6_ADDRSTRLEN];
+    inet_ntop(AF_INET6, &(ip_addr), addrstr, INET6_ADDRSTRLEN);
+    DEBUG_ARG("ip = %s", addrstr);
+#endif
+    DEBUG_ARGS((dfd, " hw addr = %02x:%02x:%02x:%02x:%02x:%02x\n",
+                ethaddr[0], ethaddr[1], ethaddr[2],
+                ethaddr[3], ethaddr[4], ethaddr[5]));
+
+    if (IN6_IS_ADDR_MULTICAST(&ip_addr) || IN6_IS_ADDR_UNSPECIFIED(&ip_addr)) {
+        /* Do not register multicast or unspecified addresses */
+        DEBUG_CALL(" abort: do not register multicast or unspecified address");
+        return;
+    }
+
+    /* Search for an entry */
+    for (i = 0; i < NDP_TABLE_SIZE; i++) {
+        if (in6_equal(&ndp_table->table[i].ip_addr, &ip_addr)) {
+            DEBUG_CALL(" already in table: update the entry");
+            /* Update the entry */
+            memcpy(ndp_table->table[i].eth_addr, ethaddr, ETH_ALEN);
+            return;
+        }
+    }
+
+    /* No entry found, create a new one */
+    DEBUG_CALL(" create new entry");
+    ndp_table->table[ndp_table->next_victim].ip_addr = ip_addr;
+    memcpy(ndp_table->table[ndp_table->next_victim].eth_addr,
+            ethaddr, ETH_ALEN);
+    ndp_table->next_victim = (ndp_table->next_victim + 1) % NDP_TABLE_SIZE;
+}
+
+bool ndp_table_search(Slirp *slirp, struct in6_addr ip_addr,
+                      uint8_t out_ethaddr[ETH_ALEN])
+{
+    NdpTable *ndp_table = &slirp->ndp_table;
+    int i;
+
+    DEBUG_CALL("ndp_table_search");
+#if !defined(_WIN32) || (_WIN32_WINNT >= 0x0600)
+    char addrstr[INET6_ADDRSTRLEN];
+    inet_ntop(AF_INET6, &(ip_addr), addrstr, INET6_ADDRSTRLEN);
+    DEBUG_ARG("ip = %s", addrstr);
+#endif
+
+    assert(!IN6_IS_ADDR_UNSPECIFIED(&ip_addr));
+
+    /* Multicast address: fec0::abcd:efgh/8 -> 33:33:ab:cd:ef:gh */
+    if (IN6_IS_ADDR_MULTICAST(&ip_addr)) {
+        out_ethaddr[0] = 0x33; out_ethaddr[1] = 0x33;
+        out_ethaddr[2] = ip_addr.s6_addr[12];
+        out_ethaddr[3] = ip_addr.s6_addr[13];
+        out_ethaddr[4] = ip_addr.s6_addr[14];
+        out_ethaddr[5] = ip_addr.s6_addr[15];
+        DEBUG_ARGS((dfd, " multicast addr = %02x:%02x:%02x:%02x:%02x:%02x\n",
+                    out_ethaddr[0], out_ethaddr[1], out_ethaddr[2],
+                    out_ethaddr[3], out_ethaddr[4], out_ethaddr[5]));
+        return 1;
+    }
+
+    for (i = 0; i < NDP_TABLE_SIZE; i++) {
+        if (in6_equal(&ndp_table->table[i].ip_addr, &ip_addr)) {
+            memcpy(out_ethaddr, ndp_table->table[i].eth_addr,  ETH_ALEN);
+            DEBUG_ARGS((dfd, " found hw addr = %02x:%02x:%02x:%02x:%02x:%02x\n",
+                        out_ethaddr[0], out_ethaddr[1], out_ethaddr[2],
+                        out_ethaddr[3], out_ethaddr[4], out_ethaddr[5]));
+            return 1;
+        }
+    }
+
+    DEBUG_CALL(" ip not found in table");
+    return 0;
+}