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, 137 insertions, 0 deletions

diff --git a/slirp/ip6.h b/slirp/ip6.h
new file mode 100644
index 0000000000..731ee72d77
--- /dev/null
+++ b/slirp/ip6.h
@@ -0,0 +1,137 @@
+/*
+ * Copyright (c) 2013
+ * Guillaume Subiron, Yann Bordenave, Serigne Modou Wagne.
+ */
+
+#ifndef SLIRP_IP6_H_
+#define SLIRP_IP6_H_
+
+#include "net/eth.h"
+
+#define ALLNODES_MULTICAST  { .s6_addr = \
+                            { 0xff, 0x02, 0x00, 0x00,\
+                            0x00, 0x00, 0x00, 0x00,\
+                            0x00, 0x00, 0x00, 0x00,\
+                            0x00, 0x00, 0x00, 0x01 } }
+
+#define SOLICITED_NODE_PREFIX { .s6_addr = \
+                            { 0xff, 0x02, 0x00, 0x00,\
+                            0x00, 0x00, 0x00, 0x00,\
+                            0x00, 0x00, 0x00, 0x01,\
+                            0xff, 0x00, 0x00, 0x00 } }
+
+#define LINKLOCAL_ADDR  { .s6_addr = \
+                        { 0xfe, 0x80, 0x00, 0x00,\
+                        0x00, 0x00, 0x00, 0x00,\
+                        0x00, 0x00, 0x00, 0x00,\
+                        0x00, 0x00, 0x00, 0x02 } }
+
+static inline bool in6_equal(const struct in6_addr *a, const struct in6_addr *b)
+{
+    return memcmp(a, b, sizeof(*a)) == 0;
+}
+
+static inline bool in6_equal_net(const struct in6_addr *a,
+                                 const struct in6_addr *b,
+                                 int prefix_len)
+{
+    if (memcmp(a, b, prefix_len / 8) != 0) {
+        return 0;
+    }
+
+    if (prefix_len % 8 == 0) {
+        return 1;
+    }
+
+    return a->s6_addr[prefix_len / 8] >> (8 - (prefix_len % 8))
+        == b->s6_addr[prefix_len / 8] >> (8 - (prefix_len % 8));
+}
+
+static inline bool in6_equal_mach(const struct in6_addr *a,
+                                  const struct in6_addr *b,
+                                  int prefix_len)
+{
+    if (memcmp(&(a->s6_addr[(prefix_len + 7) / 8]),
+               &(b->s6_addr[(prefix_len + 7) / 8]),
+               16 - (prefix_len + 7) / 8) != 0) {
+        return 0;
+    }
+
+    if (prefix_len % 8 == 0) {
+        return 1;
+    }
+
+    return (a->s6_addr[prefix_len / 8] & ((1U << (8 - (prefix_len % 8))) - 1))
+        == (b->s6_addr[prefix_len / 8] & ((1U << (8 - (prefix_len % 8))) - 1));
+}
+
+
+#define in6_equal_router(a)\
+    ((in6_equal_net(a, &slirp->vprefix_addr6, slirp->vprefix_len)\
+      && in6_equal_mach(a, &slirp->vhost_addr6, slirp->vprefix_len))\
+  || (in6_equal_net(a, &(struct in6_addr)LINKLOCAL_ADDR, 64)\
+      && in6_equal_mach(a, &slirp->vhost_addr6, 64)))
+
+#define in6_equal_dns(a) 0
+
+#define in6_equal_host(a)\
+    (in6_equal_router(a) || in6_equal_dns(a))
+
+#define in6_solicitednode_multicast(a)\
+    (in6_equal_net(a, &(struct in6_addr)SOLICITED_NODE_PREFIX, 104))
+
+/* Compute emulated host MAC address from its ipv6 address */
+static inline void in6_compute_ethaddr(struct in6_addr ip,
+                                       uint8_t eth[ETH_ALEN])
+{
+    eth[0] = 0x52;
+    eth[1] = 0x56;
+    memcpy(&eth[2], &ip.s6_addr[16 - (ETH_ALEN - 2)], ETH_ALEN - 2);
+}
+
+/*
+ * Definitions for internet protocol version 6.
+ * Per RFC 2460, December 1998.
+ */
+#define IP6VERSION      6
+#define IP6_HOP_LIMIT 255
+
+/*
+ * Structure of an internet header, naked of options.
+ */
+struct ip6 {
+#ifdef HOST_WORDS_BIGENDIAN
+    uint32_t
+        ip_v:4,         /* version */
+        ip_tc_hi:4,     /* traffic class */
+        ip_tc_lo:4,
+        ip_fl_hi:4,     /* flow label */
+        ip_fl_lo:16;
+#else
+    uint32_t
+        ip_tc_hi:4,
+        ip_v:4,
+        ip_fl_hi:4,
+        ip_tc_lo:4,
+        ip_fl_lo:16;
+#endif
+    uint16_t    ip_pl;               /* payload length */
+    uint8_t     ip_nh;               /* next header */
+    uint8_t     ip_hl;               /* hop limit */
+    struct in6_addr ip_src, ip_dst;  /* source and dest address */
+} QEMU_PACKED;
+
+/*
+ * IPv6 pseudo-header used by upper-layer protocols
+ */
+struct ip6_pseudohdr {
+    struct      in6_addr ih_src;  /* source internet address */
+    struct      in6_addr ih_dst;  /* destination internet address */
+    uint32_t    ih_pl;            /* upper-layer packet length */
+    uint16_t    ih_zero_hi;       /* zero */
+    uint8_t     ih_zero_lo;       /* zero */
+    uint8_t     ih_nh;            /* next header */
+} QEMU_PACKED;
+
+
+#endif