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, 203 insertions, 0 deletions

diff --git a/slirp/ip6_icmp.h b/slirp/ip6_icmp.h
new file mode 100644
index 0000000..b2c40d6
--- /dev/null
+++ b/slirp/ip6_icmp.h
@@ -0,0 +1,203 @@
+/*
+ * Copyright (c) 2013
+ * Guillaume Subiron, Yann Bordenave, Serigne Modou Wagne.
+ */
+
+#ifndef SLIRP_NETINET_ICMP6_H_
+#define SLIRP_NETINET_ICMP6_H_
+
+/*
+ * Interface Control Message Protocol version 6 Definitions.
+ * Per RFC 4443, March 2006.
+ *
+ * Network Discover Protocol Definitions.
+ * Per RFC 4861, September 2007.
+ */
+
+struct icmp6_echo { /* Echo Messages */
+    uint16_t id;
+    uint16_t seq_num;
+};
+
+/*
+ * NDP Messages
+ */
+struct ndp_rs {     /* Router Solicitation Message */
+    uint32_t reserved;
+};
+
+struct ndp_ra {     /* Router Advertisement Message */
+    uint8_t chl;    /* Cur Hop Limit */
+#ifdef HOST_WORDS_BIGENDIAN
+    uint8_t
+        M:1,
+        O:1,
+        reserved:6;
+#else
+    uint8_t
+        reserved:6,
+        O:1,
+        M:1;
+#endif
+    uint16_t lifetime;      /* Router Lifetime */
+    uint32_t reach_time;    /* Reachable Time */
+    uint32_t retrans_time;  /* Retrans Timer */
+} QEMU_PACKED;
+
+struct ndp_ns {     /* Neighbor Solicitation Message */
+    uint32_t reserved;
+    struct in6_addr target; /* Target Address */
+} QEMU_PACKED;
+
+struct ndp_na {     /* Neighbor Advertisement Message */
+#ifdef HOST_WORDS_BIGENDIAN
+    uint32_t
+        R:1,                /* Router Flag */
+        S:1,                /* Solicited Flag */
+        O:1,                /* Override Flag */
+        reserved_hi:5,
+        reserved_lo:24;
+#else
+    uint32_t
+        reserved_hi:5,
+        O:1,
+        S:1,
+        R:1,
+        reserved_lo:24;
+#endif
+    struct in6_addr target; /* Target Address */
+} QEMU_PACKED;
+
+struct ndp_redirect {
+    uint32_t reserved;
+    struct in6_addr target; /* Target Address */
+    struct in6_addr dest;   /* Destination Address */
+} QEMU_PACKED;
+
+/*
+ * Structure of an icmpv6 header.
+ */
+struct icmp6 {
+    uint8_t     icmp6_type;         /* type of message, see below */
+    uint8_t     icmp6_code;         /* type sub code */
+    uint16_t    icmp6_cksum;        /* ones complement cksum of struct */
+    union {
+        struct icmp6_echo echo;
+        struct ndp_rs ndp_rs;
+        struct ndp_ra ndp_ra;
+        struct ndp_ns ndp_ns;
+        struct ndp_na ndp_na;
+        struct ndp_redirect ndp_redirect;
+    } icmp6_body;
+#define icmp6_echo icmp6_body.echo
+#define icmp6_nrs icmp6_body.ndp_rs
+#define icmp6_nra icmp6_body.ndp_ra
+#define icmp6_nns icmp6_body.ndp_ns
+#define icmp6_nna icmp6_body.ndp_na
+#define icmp6_redirect icmp6_body.ndp_redirect
+} QEMU_PACKED;
+
+#define ICMP6_MINLEN    4
+#define ICMP6_ECHO_MINLEN   8
+#define ICMP6_NDP_RS_MINLEN 8
+#define ICMP6_NDP_RA_MINLEN 16
+#define ICMP6_NDP_NS_MINLEN 24
+#define ICMP6_NDP_NA_MINLEN 24
+#define ICMP6_NDP_REDIRECT_MINLEN 40
+
+/*
+ * NDP Options
+ */
+struct ndpopt {
+    uint8_t     ndpopt_type;                    /* Option type */
+    uint8_t     ndpopt_len;                     /* /!\ In units of 8 octets */
+    union {
+        unsigned char   linklayer_addr[6];      /* Source/Target Link-layer */
+        struct prefixinfo {                     /* Prefix Information */
+            uint8_t     prefix_length;
+#ifdef HOST_WORDS_BIGENDIAN
+            uint8_t     L:1, A:1, reserved1:6;
+#else
+            uint8_t     reserved1:6, A:1, L:1;
+#endif
+            uint32_t    valid_lt;               /* Valid Lifetime */
+            uint32_t    pref_lt;                /* Preferred Lifetime */
+            uint32_t    reserved2;
+            struct in6_addr prefix;
+        } QEMU_PACKED prefixinfo;
+    } ndpopt_body;
+#define ndpopt_linklayer ndpopt_body.linklayer_addr
+#define ndpopt_prefixinfo ndpopt_body.prefixinfo
+} QEMU_PACKED;
+
+/* NDP options type */
+#define NDPOPT_LINKLAYER_SOURCE     1   /* Source Link-Layer Address */
+#define NDPOPT_LINKLAYER_TARGET     2   /* Target Link-Layer Address */
+#define NDPOPT_PREFIX_INFO          3   /* Prefix Information */
+
+/* NDP options size, in octets. */
+#define NDPOPT_LINKLAYER_LEN    8
+#define NDPOPT_PREFIXINFO_LEN   32
+
+/*
+ * Definition of type and code field values.
+ * Per https://www.iana.org/assignments/icmpv6-parameters/icmpv6-parameters.xml
+ * Last Updated 2012-11-12
+ */
+
+/* Errors */
+#define ICMP6_UNREACH   1   /* Destination Unreachable */
+#define     ICMP6_UNREACH_NO_ROUTE      0   /* no route to dest */
+#define     ICMP6_UNREACH_DEST_PROHIB   1   /* com with dest prohibited */
+#define     ICMP6_UNREACH_SCOPE         2   /* beyond scope of src addr */
+#define     ICMP6_UNREACH_ADDRESS       3   /* address unreachable */
+#define     ICMP6_UNREACH_PORT          4   /* port unreachable */
+#define     ICMP6_UNREACH_SRC_FAIL      5   /* src addr failed */
+#define     ICMP6_UNREACH_REJECT_ROUTE  6   /* reject route to dest */
+#define     ICMP6_UNREACH_SRC_HDR_ERROR 7   /* error in src routing header */
+#define ICMP6_TOOBIG    2   /* Packet Too Big */
+#define ICMP6_TIMXCEED  3   /* Time Exceeded */
+#define     ICMP6_TIMXCEED_INTRANS      0   /* hop limit exceeded in transit */
+#define     ICMP6_TIMXCEED_REASS        1   /* ttl=0 in reass */
+#define ICMP6_PARAMPROB 4   /* Parameter Problem */
+#define     ICMP6_PARAMPROB_HDR_FIELD   0   /* err header field */
+#define     ICMP6_PARAMPROB_NXTHDR_TYPE 1   /* unrecognized Next Header type */
+#define     ICMP6_PARAMPROB_IPV6_OPT    2   /* unrecognized IPv6 option */
+
+/* Informational Messages */
+#define ICMP6_ECHO_REQUEST      128 /* Echo Request */
+#define ICMP6_ECHO_REPLY        129 /* Echo Reply */
+#define ICMP6_NDP_RS            133 /* Router Solicitation (NDP) */
+#define ICMP6_NDP_RA            134 /* Router Advertisement (NDP) */
+#define ICMP6_NDP_NS            135 /* Neighbor Solicitation (NDP) */
+#define ICMP6_NDP_NA            136 /* Neighbor Advertisement (NDP) */
+#define ICMP6_NDP_REDIRECT      137 /* Redirect Message (NDP) */
+
+/*
+ * Router Configuration Variables (rfc4861#section-6)
+ */
+#define NDP_IsRouter                1
+#define NDP_AdvSendAdvertisements   1
+#define NDP_MaxRtrAdvInterval       600000
+#define NDP_MinRtrAdvInterval       ((NDP_MaxRtrAdvInterval >= 9) ? \
+                                        NDP_MaxRtrAdvInterval / 3 : \
+                                        NDP_MaxRtrAdvInterval)
+#define NDP_AdvManagedFlag          0
+#define NDP_AdvOtherConfigFlag      0
+#define NDP_AdvLinkMTU              0
+#define NDP_AdvReachableTime        0
+#define NDP_AdvRetransTime          0
+#define NDP_AdvCurHopLimit          64
+#define NDP_AdvDefaultLifetime      ((3 * NDP_MaxRtrAdvInterval) / 1000)
+#define NDP_AdvValidLifetime        86400
+#define NDP_AdvOnLinkFlag           1
+#define NDP_AdvPrefLifetime         14400
+#define NDP_AdvAutonomousFlag       1
+
+void icmp6_init(Slirp *slirp);
+void icmp6_cleanup(Slirp *slirp);
+void icmp6_input(struct mbuf *);
+void ndp_send_ra(Slirp *slirp);
+void ndp_send_ns(Slirp *slirp, struct in6_addr addr);
+
+#endif