pespin has uploaded this change for review. (
https://gerrit.osmocom.org/c/libosmo-netif/+/42464?usp=email )
Change subject: Introduce API osmo_icmpv6
......................................................................
Introduce API osmo_icmpv6
icmpv6.* files are copied from osmo-ggsn.git 1.14.0
(ebd1bf8adbc8d5bec9e36d70e3a78e8838226e7a).
Change-Id: I78ec7270c717af0a1b8ffd9398cd69ea7a0dbee2
---
M TODO-RELEASE
M include/osmocom/netif/Makefile.am
A include/osmocom/netif/icmpv6.h
M src/Makefile.am
A src/icmpv6.c
5 files changed, 323 insertions(+), 0 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/libosmo-netif refs/changes/64/42464/1
diff --git a/TODO-RELEASE b/TODO-RELEASE
index 7aebf84..89a240e 100644
--- a/TODO-RELEASE
+++ b/TODO-RELEASE
@@ -8,3 +8,4 @@
# If any interfaces have been removed or changed since the last public
release: c:r:0.
#library what description / commit summary line
netif add osmo_ip_checksum API
+netif add osmo_icmpv6 API
diff --git a/include/osmocom/netif/Makefile.am
b/include/osmocom/netif/Makefile.am
index f509221..1a0cce4 100644
--- a/include/osmocom/netif/Makefile.am
+++ b/include/osmocom/netif/Makefile.am
@@ -20,6 +20,7 @@
osmonetif_HEADERS = \
amr.h \
datagram.h \
+ icmpv6.h \
ip_checksum.h \
ipa.h \
ipa_unit.h \
diff --git a/include/osmocom/netif/icmpv6.h b/include/osmocom/netif/icmpv6.h
new file mode 100644
index 0000000..94d97fc
--- /dev/null
+++ b/include/osmocom/netif/icmpv6.h
@@ -0,0 +1,105 @@
+#pragma once
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <netinet/in.h>
+
+#include <osmocom/core/msgb.h>
+#include <osmocom/core/endian.h>
+
+#define ICMPv6_OPT_TYPE_PREFIX_INFO 0x03
+
+struct osmo_icmpv6_hdr {
+ uint8_t type;
+ uint8_t code;
+ uint16_t csum;
+} __attribute__ ((packed));
+
+struct osmo_icmpv6_echo_hdr {
+ struct osmo_icmpv6_hdr hdr;
+ uint16_t ident; /* Identifier */
+ uint16_t seq; /* Sequence number */
+ uint8_t data[0]; /* Data */
+} __attribute__ ((packed));
+
+/* RFC4861 Section 4.1 */
+struct osmo_icmpv6_rsol_hdr {
+ struct osmo_icmpv6_hdr hdr;
+ uint32_t reserved;
+ uint8_t options[0];
+} __attribute__ ((packed));
+
+/* RFC4861 Section 4.2 */
+struct osmo_icmpv6_radv_hdr {
+ struct osmo_icmpv6_hdr hdr;
+ uint8_t cur_ho_limit;
+#if OSMO_IS_LITTLE_ENDIAN
+ uint8_t res:6,
+ m:1,
+ o:1;
+#elif OSMO_IS_BIG_ENDIAN
+/* auto-generated from the little endian part above
(libosmocore/contrib/struct_endianness.py) */
+ uint8_t o:1, m:1, res:6;
+#endif
+ uint16_t router_lifetime;
+ uint32_t reachable_time;
+ uint32_t retrans_timer;
+ uint8_t options[0];
+} __attribute__ ((packed));
+
+
+/* RFC4861 Section 4.6 */
+struct osmo_icmpv6_opt_hdr {
+ uint8_t type;
+ /* length in units of 8 octets, including type+len! */
+ uint8_t len;
+ uint8_t data[0];
+} __attribute__ ((packed));
+
+/* RFC4861 Section 4.6.2 */
+struct osmo_icmpv6_opt_prefix {
+ struct osmo_icmpv6_opt_hdr hdr;
+ uint8_t prefix_len;
+#if OSMO_IS_LITTLE_ENDIAN
+ uint8_t res:6,
+ a:1,
+ l:1;
+#elif OSMO_IS_BIG_ENDIAN
+/* auto-generated from the little endian part above
(libosmocore/contrib/struct_endianness.py) */
+ uint8_t l:1, a:1, res:6;
+#endif
+ uint32_t valid_lifetime;
+ uint32_t preferred_lifetime;
+ uint32_t res2;
+ uint8_t prefix[16];
+} __attribute__ ((packed));
+
+/* RFC4861 Section 4.6.4 */
+struct osmo_icmpv6_opt_mtu {
+ struct osmo_icmpv6_opt_hdr hdr;
+ uint16_t reserved;
+ uint32_t mtu;
+} __attribute__ ((packed));
+
+uint16_t osmo_icmpv6_prepend_ip6hdr(struct msgb *msg, const struct in6_addr
*saddr,
+ const struct in6_addr *daddr);
+
+struct msgb *osmo_icmpv6_construct_rs(const struct in6_addr *saddr);
+struct msgb *osmo_icmpv6_construct_ra(const struct in6_addr *saddr,
+ const struct in6_addr *daddr,
+ const struct in6_addr *prefix,
+ uint32_t mtu);
+
+bool osmo_icmpv6_validate_router_solicit(const uint8_t *pack, unsigned len);
+struct osmo_icmpv6_radv_hdr *osmo_icmpv6_validate_router_adv(const uint8_t
*pack, unsigned len);
+
+#define foreach_icmpv6_opt(icmpv6_pkt, icmpv6_len, opt_hdr) \
+ for (opt_hdr = (struct osmo_icmpv6_opt_hdr *)(icmpv6_pkt)->options; \
+ (uint8_t *)(opt_hdr) + sizeof(struct osmo_icmpv6_opt_hdr) <=
(((uint8_t *)(icmpv6_pkt)) + (icmpv6_len)); \
+ opt_hdr = (struct osmo_icmpv6_opt_hdr *)((uint8_t *)(opt_hdr) +
(opt_hdr)->len) \
+ )
+
+/* RFC3307 link-local scope multicast address */
+extern const struct in6_addr osmo_icmpv6_all_router_mcast_addr;
+
+extern const uint8_t osmo_icmpv6_solicited_node_mcast_addr_prefix[13];
diff --git a/src/Makefile.am b/src/Makefile.am
index 4484e02..8c2b95b 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -15,6 +15,7 @@
libosmonetif_la_SOURCES = amr.c \
datagram.c \
+ icmpv6.c \
ip_checksum.c \
ipa.c \
ipa_keepalive.c \
diff --git a/src/icmpv6.c b/src/icmpv6.c
new file mode 100644
index 0000000..69e03dd
--- /dev/null
+++ b/src/icmpv6.c
@@ -0,0 +1,215 @@
+/* Minimal ICMPv6 code for generating router advertisements as required by
+ * relevant 3GPP specs for a GGSN with IPv6 PDP contexts */
+
+/* (C) 2017 by Harald Welte <[email protected]>
+ *
+ * The contents of this file may be used under the terms of the GNU
+ * General Public License Version 2, provided that the above copyright
+ * notice and this permission notice is included in all copies or
+ * substantial portions of the software.
+ */
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <string.h>
+#include <netinet/in.h>
+#if defined(__FreeBSD__)
+#include <sys/types.h> /* FreeBSD 10.x needs this before ip6.h */
+#include <sys/endian.h>
+#endif
+#include <netinet/ip6.h>
+
+#include <osmocom/core/msgb.h>
+#include <osmocom/core/utils.h>
+
+#include <osmocom/netif/ip_checksum.h>
+#include <osmocom/netif/icmpv6.h>
+
+/* 29.061 11.2.1.3.4 IPv6 Router Configuration Variables in GGSN */
+#define GGSN_MaxRtrAdvInterval 21600 /* 6 hours */
+#define GGSN_MinRtrAdvInterval 16200 /* 4.5 hours */
+#define GGSN_AdvValidLifetime 0xffffffff /* infinite */
+#define GGSN_AdvPreferredLifetime 0xffffffff /* infinite */
+
+/* RFC3307 link-local scope multicast address */
+const struct in6_addr osmo_icmpv6_all_router_mcast_addr = {
+ .s6_addr = { 0xff, 0x02, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2 }
+};
+
+
+/* RFC4291 link-local solicited-node multicast address, FF02:0:0:0:0:1:FF,
104 bits = 13 bytes */
+const uint8_t osmo_icmpv6_solicited_node_mcast_addr_prefix[13] = {
+ 0xff, 0x02, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x01,
+ 0xFF
+};
+
+/* Prepends the ipv6 header and returns checksum content */
+uint16_t icmpv6_prepend_ip6hdr(struct msgb *msg, const struct in6_addr *saddr,
+ const struct in6_addr *daddr)
+{
+ uint32_t len;
+ uint16_t skb_csum;
+ struct ip6_hdr *i6h;
+
+ /* checksum */
+ skb_csum = osmo_ip_checksum_csum_partial(msgb_data(msg),
msgb_length(msg), 0);
+ len = msgb_length(msg);
+ skb_csum = osmo_ip_checksum_csum_ipv6_magic(saddr, daddr, len,
IPPROTO_ICMPV6, skb_csum);
+
+ /* Push IPv6 header in front of ICMPv6 packet */
+ i6h = (struct ip6_hdr *) msgb_push(msg, sizeof(*i6h));
+ /* 4 bits version, 8 bits TC, 20 bits flow-ID */
+ i6h->ip6_ctlun.ip6_un1.ip6_un1_flow = htonl(0x60000000);
+ i6h->ip6_ctlun.ip6_un1.ip6_un1_plen = htons(len);
+ i6h->ip6_ctlun.ip6_un1.ip6_un1_nxt = IPPROTO_ICMPV6;
+ i6h->ip6_ctlun.ip6_un1.ip6_un1_hlim = 255;
+ i6h->ip6_src = *saddr;
+ i6h->ip6_dst = *daddr;
+ return skb_csum;
+}
+
+/*! construct a RFC4861 compliant ICMPv6 router soliciation
+ * \param[in] saddr Source IPv6 address for router advertisement
+ * \param[in] daddr Destination IPv6 address for router advertisement IPv6
header
+ * \param[in] prefix The single prefix to be advertised (/64 implied!)
+ * \returns callee-allocated message buffer containing router advertisement */
+struct msgb *osmo_icmpv6_construct_rs(const struct in6_addr *saddr)
+{
+ struct msgb *msg = msgb_alloc_headroom(512, 128, "IPv6 RS");
+ struct osmo_icmpv6_rsol_hdr *rs;
+ OSMO_ASSERT(msg);
+ rs = (struct osmo_icmpv6_rsol_hdr *) msgb_put(msg, sizeof(*rs));
+ rs->hdr.type = 133; /* see RFC4861 4.1 */
+ rs->hdr.code = 0; /* see RFC4861 4.1 */
+ rs->hdr.csum = 0; /* updated below */
+ rs->reserved = 0; /* see RFC4861 4.1 */
+
+ rs->hdr.csum = icmpv6_prepend_ip6hdr(msg, saddr,
&osmo_icmpv6_all_router_mcast_addr);
+
+ return msg;
+}
+/*! construct a 3GPP 29.061 compliant router advertisement for a given prefix
+ * \param[in] saddr Source IPv6 address for router advertisement
+ * \param[in] daddr Destination IPv6 address for router advertisement IPv6
header
+ * \param[in] prefix The single prefix to be advertised (/64 implied!)
+ * \returns callee-allocated message buffer containing router advertisement */
+struct msgb *osmo_icmpv6_construct_ra(const struct in6_addr *saddr,
+ const struct in6_addr *daddr,
+ const struct in6_addr *prefix,
+ uint32_t mtu)
+{
+ struct msgb *msg = msgb_alloc_headroom(512, 128, "IPv6 RA");
+ struct osmo_icmpv6_radv_hdr *ra;
+ struct osmo_icmpv6_opt_prefix *ra_opt_pref;
+ struct osmo_icmpv6_opt_mtu *ra_opt_mtu;
+
+ OSMO_ASSERT(msg);
+
+ ra = (struct osmo_icmpv6_radv_hdr *) msgb_put(msg, sizeof(*ra));
+ ra->hdr.type = 134; /* see RFC4861 4.2 */
+ ra->hdr.code = 0; /* see RFC4861 4.2 */
+ ra->hdr.csum = 0; /* updated below */
+ ra->cur_ho_limit = 64; /* seems reasonable? */
+ /* the GGSN shall leave the M-flag cleared in the Router
+ * Advertisement messages */
+ ra->m = 0;
+ /* The GGSN may set the O-flag if there are additional
+ * configuration parameters that need to be fetched by the MS */
+ ra->o = 0; /* no DHCPv6 */
+ ra->res = 0;
+ /* RFC4861 Default: 3 * MaxRtrAdvInterval */
+ ra->router_lifetime = htons(3*GGSN_MaxRtrAdvInterval);
+ ra->reachable_time = 0; /* Unspecified */
+
+ /* RFC4861 Section 4.6.2 */
+ ra_opt_pref = (struct osmo_icmpv6_opt_prefix *) msgb_put(msg,
sizeof(*ra_opt_pref));
+ ra_opt_pref->hdr.type = 3; /* RFC4861 4.6.2 */
+ ra_opt_pref->hdr.len = 4; /* RFC4861 4.6.2 */
+ ra_opt_pref->prefix_len = 64; /* only prefix length as per 3GPP */
+ /* The Prefix is contained in the Prefix Information Option of
+ * the Router Advertisements and shall have the A-flag set
+ * and the L-flag cleared */
+ ra_opt_pref->a = 1;
+ ra_opt_pref->l = 0;
+ ra_opt_pref->res = 0;
+ /* The lifetime of the prefix shall be set to infinity */
+ ra_opt_pref->valid_lifetime = htonl(GGSN_AdvValidLifetime);
+ ra_opt_pref->preferred_lifetime = htonl(GGSN_AdvPreferredLifetime);
+ ra_opt_pref->res2 = 0;
+ memcpy(ra_opt_pref->prefix, prefix, sizeof(ra_opt_pref->prefix));
+
+ /* RFC4861 Section 4.6.4, MTU */
+ ra_opt_mtu = (struct osmo_icmpv6_opt_mtu *) msgb_put(msg,
sizeof(*ra_opt_mtu));
+ ra_opt_mtu->hdr.type = 5; /* RFC4861 4.6.4 */
+ ra_opt_mtu->hdr.len = 1; /* RFC4861 4.6.4 */
+ ra_opt_mtu->reserved = 0;
+ ra_opt_mtu->mtu = htonl(mtu);
+
+ /* The Prefix is contained in the Prefix Information Option of
+ * the Router Advertisements and shall have the A-flag set
+ * and the L-flag cleared */
+ ra_opt_pref->a = 1;
+ ra_opt_pref->l = 0;
+ ra_opt_pref->res = 0;
+ /* The lifetime of the prefix shall be set to infinity */
+ ra_opt_pref->valid_lifetime = htonl(GGSN_AdvValidLifetime);
+ ra_opt_pref->preferred_lifetime = htonl(GGSN_AdvPreferredLifetime);
+ ra_opt_pref->res2 = 0;
+ memcpy(ra_opt_pref->prefix, prefix, sizeof(ra_opt_pref->prefix));
+
+ /* checksum */
+ ra->hdr.csum = icmpv6_prepend_ip6hdr(msg, saddr, daddr);
+
+ return msg;
+}
+
+/* Validate an ICMPv6 router solicitation according to RFC4861 6.1.1 */
+bool osmo_icmpv6_validate_router_solicit(const uint8_t *pack, unsigned len)
+{
+ const struct ip6_hdr *ip6h = (struct ip6_hdr *)pack;
+ //const struct icmpv6_hdr *ic6h = (struct icmpv6_hdr *) (pack +
sizeof(*ip6h));
+
+ /* Hop limit field must have 255 */
+ if (ip6h->ip6_ctlun.ip6_un1.ip6_un1_hlim != 255)
+ return false;
+ /* FIXME: ICMP checksum is valid */
+ /* ICMP length (derived from IP length) is 8 or more octets */
+ if (ip6h->ip6_ctlun.ip6_un1.ip6_un1_plen < 8)
+ return false;
+ /* FIXME: All included options have a length > 0 */
+ /* FIXME: If IP source is unspecified, no source link-layer addr option
*/
+ return true;
+}
+
+/* Validate an ICMPv6 router advertisement according to RFC4861 6.1.2.
+ Returns pointer packet header on success, NULL otherwise. */
+struct osmo_icmpv6_radv_hdr *osmo_icmpv6_validate_router_adv(const uint8_t
*pack, unsigned len)
+{
+ const struct ip6_hdr *ip6h = (struct ip6_hdr *)pack;
+ const struct osmo_icmpv6_hdr *ic6h = (struct osmo_icmpv6_hdr *) (pack +
sizeof(*ip6h));
+
+ /* ICMP length (derived from IP length) is 16 or more octets */
+ if (len < sizeof(*ip6h) + 16)
+ return NULL;
+
+ if (ic6h->type != 134) /* router advertismenet type */
+ return NULL;
+
+ /*Routers must use their link-local address */
+ if (!IN6_IS_ADDR_LINKLOCAL(&ip6h->ip6_src))
+ return NULL;
+ /* Hop limit field must have 255 */
+ if (ip6h->ip6_ctlun.ip6_un1.ip6_un1_hlim != 255)
+ return NULL;
+ /* ICMP Code is 0 */
+ if (ic6h->code != 0)
+ return NULL;
+ /* ICMP length (derived from IP length) is 16 or more octets */
+ if (ip6h->ip6_ctlun.ip6_un1.ip6_un1_plen < 16)
+ return NULL;
+ /* FIXME: All included options have a length > 0 */
+ /* FIXME: If IP source is unspecified, no source link-layer addr option
*/
+ return (struct osmo_icmpv6_radv_hdr *)ic6h;
+}
--
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Gerrit-MessageType: newchange
Gerrit-Project: libosmo-netif
Gerrit-Branch: master
Gerrit-Change-Id: I78ec7270c717af0a1b8ffd9398cd69ea7a0dbee2
Gerrit-Change-Number: 42464
Gerrit-PatchSet: 1
Gerrit-Owner: pespin <[email protected]>
