Move icmpv6 and checksum files from ggsn/ dir to lib/

They will be required by sgsnemu to implement ICMPv6 Router
Soliciations.

Change-Id: Ie878604f0fc0169cc98a1e9eee64b14d76be2c45
diff --git a/ggsn/Makefile.am b/ggsn/Makefile.am
index ca389f0..eea7c6e 100644
--- a/ggsn/Makefile.am
+++ b/ggsn/Makefile.am
@@ -12,4 +12,4 @@
 endif
 
 osmo_ggsn_DEPENDENCIES = ../gtp/libgtp.la ../lib/libmisc.a
-osmo_ggsn_SOURCES = ggsn_main.c ggsn_vty.c ggsn.c ggsn.h sgsn.c sgsn.h icmpv6.c icmpv6.h checksum.c checksum.h pco.c pco.h
+osmo_ggsn_SOURCES = ggsn_main.c ggsn_vty.c ggsn.c ggsn.h sgsn.c sgsn.h pco.c pco.h
diff --git a/ggsn/checksum.c b/ggsn/checksum.c
deleted file mode 100644
index 4b23897..0000000
--- a/ggsn/checksum.c
+++ /dev/null
@@ -1,211 +0,0 @@
-/*
- *
- * INET		An implementation of the TCP/IP protocol suite for the LINUX
- *		operating system.  INET is implemented using the  BSD Socket
- *		interface as the means of communication with the user level.
- *
- *		IP/TCP/UDP checksumming routines
- *
- * Authors:	Jorge Cwik, <jorge@laser.satlink.net>
- *		Arnt Gulbrandsen, <agulbra@nvg.unit.no>
- *		Tom May, <ftom@netcom.com>
- *		Andreas Schwab, <schwab@issan.informatik.uni-dortmund.de>
- *		Lots of code moved from tcp.c and ip.c; see those files
- *		for more names.
- *
- * 03/02/96	Jes Sorensen, Andreas Schwab, Roman Hodek:
- *		Fixed some nasty bugs, causing some horrible crashes.
- *		A: At some points, the sum (%0) was used as
- *		length-counter instead of the length counter
- *		(%1). Thanks to Roman Hodek for pointing this out.
- *		B: GCC seems to mess up if one uses too many
- *		data-registers to hold input values and one tries to
- *		specify d0 and d1 as scratch registers. Letting gcc
- *		choose these registers itself solves the problem.
- *
- *		This program is free software; you can redistribute it and/or
- *		modify it under the terms of the GNU General Public License
- *		as published by the Free Software Foundation; either version
- *		2 of the License, or (at your option) any later version.
- */
-
-/* Revised by Kenneth Albanowski for m68knommu. Basic problem: unaligned access
- kills, so most of the assembly has to go. */
-
-#if defined(__FreeBSD__)
-#define _KERNEL	/* needed on FreeBSD 10.x for s6_addr32 */
-#include <sys/types.h>
-#include <netinet/in.h>
-#include <sys/endian.h>
-#endif
-
-#include "checksum.h"
-#include <arpa/inet.h>
-
-static inline unsigned short from32to16(unsigned int x)
-{
-	/* add up 16-bit and 16-bit for 16+c bit */
-	x = (x & 0xffff) + (x >> 16);
-	/* add up carry.. */
-	x = (x & 0xffff) + (x >> 16);
-	return x;
-}
-
-static unsigned int do_csum(const unsigned char *buff, int len)
-{
-	int odd;
-	unsigned int result = 0;
-
-	if (len <= 0)
-		goto out;
-	odd = 1 & (unsigned long) buff;
-	if (odd) {
-#if BYTE_ORDER == LITTLE_ENDIAN
-		result += (*buff << 8);
-#else
-		result = *buff;
-#endif
-		len--;
-		buff++;
-	}
-	if (len >= 2) {
-		if (2 & (unsigned long) buff) {
-			result += *(unsigned short *) buff;
-			len -= 2;
-			buff += 2;
-		}
-		if (len >= 4) {
-			const unsigned char *end = buff + ((unsigned)len & ~3);
-			unsigned int carry = 0;
-			do {
-				unsigned int w = *(unsigned int *) buff;
-				buff += 4;
-				result += carry;
-				result += w;
-				carry = (w > result);
-			} while (buff < end);
-			result += carry;
-			result = (result & 0xffff) + (result >> 16);
-		}
-		if (len & 2) {
-			result += *(unsigned short *) buff;
-			buff += 2;
-		}
-	}
-	if (len & 1)
-#if BYTE_ORDER == LITTLE_ENDIAN
-		result += *buff;
-#else
-		result += (*buff << 8);
-#endif
-	result = from32to16(result);
-	if (odd)
-		result = ((result >> 8) & 0xff) | ((result & 0xff) << 8);
-out:
-	return result;
-}
-
-/*
- *	This is a version of ip_compute_csum() optimized for IP headers,
- *	which always checksum on 4 octet boundaries.
- */
-uint16_t ip_fast_csum(const void *iph, unsigned int ihl)
-{
-	return (uint16_t)~do_csum(iph, ihl*4);
-}
-
-/*
- * computes the checksum of a memory block at buff, length len,
- * and adds in "sum" (32-bit)
- *
- * returns a 32-bit number suitable for feeding into itself
- * or csum_tcpudp_magic
- *
- * this function must be called with even lengths, except
- * for the last fragment, which may be odd
- *
- * it's best to have buff aligned on a 32-bit boundary
- */
-uint32_t csum_partial(const void *buff, int len, uint32_t wsum)
-{
-	unsigned int sum = (unsigned int)wsum;
-	unsigned int result = do_csum(buff, len);
-
-	/* add in old sum, and carry.. */
-	result += sum;
-	if (sum > result)
-		result += 1;
-	return (uint32_t)result;
-}
-
-/*
- * this routine is used for miscellaneous IP-like checksums, mainly
- * in icmp.c
- */
-uint16_t ip_compute_csum(const void *buff, int len)
-{
-	return (uint16_t)~do_csum(buff, len);
-}
-
-uint16_t csum_ipv6_magic(const struct in6_addr *saddr,
-			const struct in6_addr *daddr,
-			uint32_t len, uint8_t proto, uint32_t csum)
-{
-	int carry;
-	uint32_t ulen;
-	uint32_t uproto;
-	uint32_t sum = (uint32_t)csum;
-
-	sum += (uint32_t)saddr->s6_addr32[0];
-	carry = (sum < (uint32_t)saddr->s6_addr32[0]);
-	sum += carry;
-
-	sum += (uint32_t)saddr->s6_addr32[1];
-	carry = (sum < (uint32_t)saddr->s6_addr32[1]);
-	sum += carry;
-
-	sum += (uint32_t)saddr->s6_addr32[2];
-	carry = (sum < (uint32_t)saddr->s6_addr32[2]);
-	sum += carry;
-
-	sum += (uint32_t)saddr->s6_addr32[3];
-	carry = (sum < (uint32_t)saddr->s6_addr32[3]);
-	sum += carry;
-
-	sum += (uint32_t)daddr->s6_addr32[0];
-	carry = (sum < (uint32_t)daddr->s6_addr32[0]);
-	sum += carry;
-
-	sum += (uint32_t)daddr->s6_addr32[1];
-	carry = (sum < (uint32_t)daddr->s6_addr32[1]);
-	sum += carry;
-
-	sum += (uint32_t)daddr->s6_addr32[2];
-	carry = (sum < (uint32_t)daddr->s6_addr32[2]);
-	sum += carry;
-
-	sum += (uint32_t)daddr->s6_addr32[3];
-	carry = (sum < (uint32_t)daddr->s6_addr32[3]);
-	sum += carry;
-
-	ulen = (uint32_t)htonl((uint32_t) len);
-	sum += ulen;
-	carry = (sum < ulen);
-	sum += carry;
-
-	uproto = (uint32_t)htonl(proto);
-	sum += uproto;
-	carry = (sum < uproto);
-	sum += carry;
-
-	return csum_fold((uint32_t)sum);
-}
-
-/* fold a partial checksum */
-uint16_t csum_fold(uint32_t csum)
-{
-	uint32_t sum = (uint32_t)csum;
-	sum = (sum & 0xffff) + (sum >> 16);
-	sum = (sum & 0xffff) + (sum >> 16);
-	return (uint16_t)~sum;
-}
diff --git a/ggsn/checksum.h b/ggsn/checksum.h
deleted file mode 100644
index 4b22431..0000000
--- a/ggsn/checksum.h
+++ /dev/null
@@ -1,13 +0,0 @@
-#pragma once
-#include <stdint.h>
-#include <netinet/in.h>
-
-uint16_t ip_fast_csum(const void *iph, unsigned int ihl);
-uint32_t csum_partial(const void *buff, int len, uint32_t wsum);
-uint16_t ip_compute_csum(const void *buff, int len);
-
-uint16_t csum_ipv6_magic(const struct in6_addr *saddr,
-			const struct in6_addr *daddr,
-			uint32_t len, uint8_t proto, uint32_t csum);
-
-uint16_t csum_fold(uint32_t csum);
diff --git a/ggsn/ggsn.c b/ggsn/ggsn.c
index c710984..3b10f70 100644
--- a/ggsn/ggsn.c
+++ b/ggsn/ggsn.c
@@ -54,7 +54,7 @@
 #include "../lib/util.h"
 #include "../gtp/pdp.h"
 #include "../gtp/gtp.h"
-#include "icmpv6.h"
+#include "../lib/icmpv6.h"
 #include "pco.h"
 #include "ggsn.h"
 
diff --git a/ggsn/icmpv6.c b/ggsn/icmpv6.c
deleted file mode 100644
index 12119b8..0000000
--- a/ggsn/icmpv6.c
+++ /dev/null
@@ -1,232 +0,0 @@
-/* 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 <laforge@gnumonks.org>
- *
- * 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 "checksum.h"
-
-#include "../gtp/gtp.h"
-#include "../gtp/pdp.h"
-#include "../lib/ippool.h"
-#include "../lib/syserr.h"
-#include "config.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 */
-
-struct icmpv6_hdr {
-	uint8_t type;
-	uint8_t code;
-	uint16_t csum;
-} __attribute__ ((packed));
-
-/* RFC4861 Section 4.2 */
-struct icmpv6_radv_hdr {
-	struct icmpv6_hdr hdr;
-	uint8_t cur_ho_limit;
-#if BYTE_ORDER == LITTLE_ENDIAN
-	uint8_t res:6,
-		m:1,
-		o:1;
-#elif BYTE_ORDER == BIG_ENDIAN
-	uint8_t m:1,
-		o:1,
-		res:6;
-#else
-# error	"Please fix <bits/endian.h>"
-#endif
-	uint16_t router_lifetime;
-	uint32_t reachable_time;
-	uint32_t retrans_timer;
-	uint8_t options[0];
-} __attribute__ ((packed));
-
-/* RFC4861 Section 4.6 */
-struct 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 icmpv6_opt_prefix {
-	struct icmpv6_opt_hdr hdr;
-	uint8_t prefix_len;
-#if BYTE_ORDER == LITTLE_ENDIAN
-	uint8_t res:6,
-		a:1,
-		l:1;
-#elif BYTE_ORDER == BIG_ENDIAN
-	uint8_t l:1,
-		a:1,
-		res:6;
-#else
-# error	"Please fix <bits/endian.h>"
-#endif
-	uint32_t valid_lifetime;
-	uint32_t preferred_lifetime;
-	uint32_t res2;
-	uint8_t prefix[16];
-} __attribute__ ((packed));
-
-
-/*! 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 *icmpv6_construct_ra(const struct in6_addr *saddr,
-				 const struct in6_addr *daddr,
-				 const struct in6_addr *prefix)
-{
-	struct msgb *msg = msgb_alloc_headroom(512,128, "IPv6 RA");
-	struct icmpv6_radv_hdr *ra;
-	struct icmpv6_opt_prefix *ra_opt_pref;
-	struct ip6_hdr *i6h;
-	uint32_t len;
-	uint16_t skb_csum;
-
-	OSMO_ASSERT(msg);
-
-	ra = (struct 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 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));
-
-	/* checksum */
-	skb_csum = csum_partial(msgb_data(msg), msgb_length(msg), 0);
-	len = msgb_length(msg);
-	ra->hdr.csum = 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 msg;
-}
-
-/* Walidate an ICMPv6 router solicitation according to RFC4861 6.1.1 */
-static bool 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;
-}
-
-/* handle incoming packets to the all-routers multicast address */
-int handle_router_mcast(struct gsn_t *gsn, struct pdp_t *pdp,
-			const struct in6_addr *pdp_prefix,
-			const struct in6_addr *own_ll_addr,
-			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));
-	struct msgb *msg;
-
-	if (len < sizeof(*ip6h)) {
-		LOGP(DICMP6, LOGL_NOTICE, "Packet too short: %u bytes\n", len);
-		return -1;
-	}
-
-	/* we only treat ICMPv6 here */
-	if (ip6h->ip6_ctlun.ip6_un1.ip6_un1_nxt != IPPROTO_ICMPV6) {
-		LOGP(DICMP6, LOGL_DEBUG, "Ignoring non-ICMP to all-routers mcast\n");
-		return 0;
-	}
-
-	if (len < sizeof(*ip6h) + sizeof(*ic6h)) {
-		LOGP(DICMP6, LOGL_NOTICE, "Short ICMPv6 packet: %s\n", osmo_hexdump(pack, len));
-		return -1;
-	}
-
-	switch (ic6h->type) {
-	case 133:	/* router solicitation */
-		if (ic6h->code != 0) {
-			LOGP(DICMP6, LOGL_NOTICE, "ICMPv6 type 133 but code %d\n", ic6h->code);
-			return -1;
-		}
-		if (!icmpv6_validate_router_solicit(pack, len)) {
-			LOGP(DICMP6, LOGL_NOTICE, "Invalid Router Solicitation: %s\n",
-				osmo_hexdump(pack, len));
-			return -1;
-		}
-		/* Send router advertisement from GGSN link-local
-		 * address to MS link-local address, including prefix
-		 * allocated to this PDP context */
-		msg = icmpv6_construct_ra(own_ll_addr, &ip6h->ip6_src, pdp_prefix);
-		/* Send the constructed RA to the MS */
-		gtp_data_req(gsn, pdp, msgb_data(msg), msgb_length(msg));
-		msgb_free(msg);
-		break;
-	default:
-		LOGP(DICMP6, LOGL_DEBUG, "Unknown ICMPv6 type %u\n", ic6h->type);
-		break;
-	}
-	return 0;
-}
diff --git a/ggsn/icmpv6.h b/ggsn/icmpv6.h
deleted file mode 100644
index bf91e27..0000000
--- a/ggsn/icmpv6.h
+++ /dev/null
@@ -1,9 +0,0 @@
-#pragma once
-
-#include "../gtp/gtp.h"
-#include "../gtp/pdp.h"
-
-int handle_router_mcast(struct gsn_t *gsn, struct pdp_t *pdp,
-			const struct in6_addr *pdp_prefix,
-			const struct in6_addr *own_ll_addr,
-			const uint8_t *pack, unsigned len);