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gems-kernel/source/THIRDPARTY/xnu/bsd/net/nat464_utils.c
Sam Sneed f5727805f2 add darwin/xnu functionality
2024-06-03 11:29:39 -05:00

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/*
* Copyright (c) 2018-2020 Apple Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
/*
* Copyright (c) 2001 Daniel Hartmeier
* Copyright (c) 2002 - 2013 Henning Brauer
* NAT64 - Copyright (c) 2010 Viagenie Inc. (http://www.viagenie.ca)
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Effort sponsored in part by the Defense Advanced Research Projects
* Agency (DARPA) and Air Force Research Laboratory, Air Force
* Materiel Command, USAF, under agreement number F30602-01-2-0537.
*
*/
#include <sys/param.h>
#include <sys/types.h>
#include <sys/mbuf.h>
#include <net/if.h>
#include <net/if_types.h>
#include <net/dlil.h>
#include <net/nat464_utils.h>
#include <net/nwk_wq.h>
#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip6.h>
#include <netinet/ip_var.h>
#include <netinet/ip_icmp.h>
#include <netinet/in_pcb.h>
#include <netinet/icmp_var.h>
#include <netinet/icmp6.h>
#include <netinet/tcp.h>
#include <netinet/udp.h>
#include <netinet/udp_var.h>
#include <os/log.h>
int clat_debug = 0;
os_log_t nat_log_handle;
static void
nat464_addr_cksum_fixup(uint16_t *, struct nat464_addr *, struct nat464_addr *,
protocol_family_t, protocol_family_t, uint8_t, boolean_t);
/* Synthesize ipv6 from ipv4 */
int
nat464_synthesize_ipv6(ifnet_t ifp, const struct in_addr *addrv4, struct in6_addr *addr)
{
static const struct in6_addr well_known_prefix = {
.__u6_addr.__u6_addr8 = {0x00, 0x64, 0xff, 0x9b, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00},
};
struct ipv6_prefix nat64prefixes[NAT64_MAX_NUM_PREFIXES];
int error = 0, i = 0;
/* Below call is not optimized as it creates a copy of prefixes */
if ((error = ifnet_get_nat64prefix(ifp, nat64prefixes)) != 0) {
return error;
}
for (i = 0; i < NAT64_MAX_NUM_PREFIXES; i++) {
if (nat64prefixes[i].prefix_len != 0) {
break;
}
}
VERIFY(i < NAT64_MAX_NUM_PREFIXES);
struct in6_addr prefix = nat64prefixes[i].ipv6_prefix;
int prefix_len = nat64prefixes[i].prefix_len;
char *ptrv4 = __DECONST(char *, addrv4);
char *ptr = __DECONST(char *, addr);
if (IN_ZERONET(ntohl(addrv4->s_addr)) || // 0.0.0.0/8 Source hosts on local network
IN_LOOPBACK(ntohl(addrv4->s_addr)) || // 127.0.0.0/8 Loopback
IN_LINKLOCAL(ntohl(addrv4->s_addr)) || // 169.254.0.0/16 Link Local
IN_DS_LITE(ntohl(addrv4->s_addr)) || // 192.0.0.0/29 DS-Lite
IN_6TO4_RELAY_ANYCAST(ntohl(addrv4->s_addr)) || // 192.88.99.0/24 6to4 Relay Anycast
IN_MULTICAST(ntohl(addrv4->s_addr)) || // 224.0.0.0/4 Multicast
INADDR_BROADCAST == addrv4->s_addr) { // 255.255.255.255/32 Limited Broadcast
return -1;
}
/* Check for the well-known prefix */
if (prefix_len == NAT64_PREFIX_LEN_96 &&
IN6_ARE_ADDR_EQUAL(&prefix, &well_known_prefix)) { // https://tools.ietf.org/html/rfc6052#section-3.1
if (IN_PRIVATE(ntohl(addrv4->s_addr)) || // 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16 Private-Use
IN_SHARED_ADDRESS_SPACE(ntohl(addrv4->s_addr))) { // 100.64.0.0/10 Shared Address Space
return -1;
}
}
memcpy(ptr, (char *)&prefix, prefix_len);
switch (prefix_len) {
case NAT64_PREFIX_LEN_96:
memcpy(ptr + 12, ptrv4, 4);
break;
case NAT64_PREFIX_LEN_64:
memcpy(ptr + 9, ptrv4, 4);
break;
case NAT64_PREFIX_LEN_56:
memcpy(ptr + 7, ptrv4, 1);
memcpy(ptr + 9, ptrv4 + 1, 3);
break;
case NAT64_PREFIX_LEN_48:
memcpy(ptr + 6, ptrv4, 2);
memcpy(ptr + 9, ptrv4 + 2, 2);
break;
case NAT64_PREFIX_LEN_40:
memcpy(ptr + 5, ptrv4, 3);
memcpy(ptr + 9, ptrv4 + 3, 1);
break;
case NAT64_PREFIX_LEN_32:
memcpy(ptr + 4, ptrv4, 4);
break;
default:
panic("NAT64-prefix len is wrong: %u", prefix_len);
}
if (clat_debug) {
char buf[MAX_IPv6_STR_LEN];
clat_log2((LOG_DEBUG, "%s synthesized %s\n", __func__,
inet_ntop(AF_INET6, (void *)addr, buf, sizeof(buf))));
}
return error;
}
/* Synthesize ipv4 from ipv6 */
int
nat464_synthesize_ipv4(ifnet_t ifp, const struct in6_addr *addr, struct in_addr *addrv4)
{
struct ipv6_prefix nat64prefixes[NAT64_MAX_NUM_PREFIXES];
int error = 0, i = 0;
/* Below call is not optimized as it creates a copy of prefixes */
if ((error = ifnet_get_nat64prefix(ifp, nat64prefixes)) != 0) {
return error;
}
for (i = 0; i < NAT64_MAX_NUM_PREFIXES; i++) {
if (nat64prefixes[i].prefix_len != 0) {
break;
}
}
VERIFY(i < NAT64_MAX_NUM_PREFIXES);
struct in6_addr prefix = nat64prefixes[i].ipv6_prefix;
int prefix_len = nat64prefixes[i].prefix_len;
char *ptrv4 = __DECONST(void *, addrv4);
char *ptr = __DECONST(void *, addr);
if (memcmp(addr, &prefix, prefix_len) != 0) {
return -1;
}
switch (prefix_len) {
case NAT64_PREFIX_LEN_96:
memcpy(ptrv4, ptr + 12, 4);
break;
case NAT64_PREFIX_LEN_64:
memcpy(ptrv4, ptr + 9, 4);
break;
case NAT64_PREFIX_LEN_56:
memcpy(ptrv4, ptr + 7, 1);
memcpy(ptrv4 + 1, ptr + 9, 3);
break;
case NAT64_PREFIX_LEN_48:
memcpy(ptrv4, ptr + 6, 2);
memcpy(ptrv4 + 2, ptr + 9, 2);
break;
case NAT64_PREFIX_LEN_40:
memcpy(ptrv4, ptr + 5, 3);
memcpy(ptrv4 + 3, ptr + 9, 1);
break;
case NAT64_PREFIX_LEN_32:
memcpy(ptrv4, ptr + 4, 4);
break;
default:
panic("NAT64-prefix len is wrong: %u",
prefix_len);
}
if (clat_debug) {
char buf[MAX_IPv4_STR_LEN];
clat_log2((LOG_DEBUG, "%s desynthesized to %s\n", __func__,
inet_ntop(AF_INET, (void *)addrv4, buf, sizeof(buf))));
}
return error;
}
#define PTR_IP(field) ((int32_t)offsetof(struct ip, field))
#define PTR_IP6(field) ((int32_t)offsetof(struct ip6_hdr, field))
/*
* Translate the ICMP header
*/
int
nat464_translate_icmp(int naf, void *arg)
{
struct icmp *icmp4;
struct icmp6_hdr *icmp6;
uint32_t mtu;
int32_t ptr = -1;
uint8_t type;
uint8_t code;
switch (naf) {
case AF_INET:
icmp6 = arg;
type = icmp6->icmp6_type;
code = icmp6->icmp6_code;
mtu = ntohl(icmp6->icmp6_mtu);
switch (type) {
case ICMP6_ECHO_REQUEST:
type = ICMP_ECHO;
break;
case ICMP6_ECHO_REPLY:
type = ICMP_ECHOREPLY;
break;
case ICMP6_DST_UNREACH:
type = ICMP_UNREACH;
switch (code) {
case ICMP6_DST_UNREACH_NOROUTE:
case ICMP6_DST_UNREACH_BEYONDSCOPE:
case ICMP6_DST_UNREACH_ADDR:
code = ICMP_UNREACH_HOST;
break;
case ICMP6_DST_UNREACH_ADMIN:
code = ICMP_UNREACH_HOST_PROHIB;
break;
case ICMP6_DST_UNREACH_NOPORT:
code = ICMP_UNREACH_PORT;
break;
default:
return -1;
}
break;
case ICMP6_PACKET_TOO_BIG:
type = ICMP_UNREACH;
code = ICMP_UNREACH_NEEDFRAG;
mtu -= 20;
break;
case ICMP6_TIME_EXCEEDED:
type = ICMP_TIMXCEED;
break;
case ICMP6_PARAM_PROB:
switch (code) {
case ICMP6_PARAMPROB_HEADER:
type = ICMP_PARAMPROB;
code = ICMP_PARAMPROB_ERRATPTR;
ptr = ntohl(icmp6->icmp6_pptr);
if (ptr == PTR_IP6(ip6_vfc)) {
; /* preserve */
} else if (ptr == PTR_IP6(ip6_vfc) + 1) {
ptr = PTR_IP(ip_tos);
} else if (ptr == PTR_IP6(ip6_plen) ||
ptr == PTR_IP6(ip6_plen) + 1) {
ptr = PTR_IP(ip_len);
} else if (ptr == PTR_IP6(ip6_nxt)) {
ptr = PTR_IP(ip_p);
} else if (ptr == PTR_IP6(ip6_hlim)) {
ptr = PTR_IP(ip_ttl);
} else if (ptr >= PTR_IP6(ip6_src) &&
ptr < PTR_IP6(ip6_dst)) {
ptr = PTR_IP(ip_src);
} else if (ptr >= PTR_IP6(ip6_dst) &&
ptr < (int32_t)sizeof(struct ip6_hdr)) {
ptr = PTR_IP(ip_dst);
} else {
return -1;
}
break;
case ICMP6_PARAMPROB_NEXTHEADER:
type = ICMP_UNREACH;
code = ICMP_UNREACH_PROTOCOL;
break;
default:
return -1;
}
break;
default:
return -1;
}
icmp6->icmp6_type = type;
icmp6->icmp6_code = code;
/* aligns well with a icmpv4 nextmtu */
icmp6->icmp6_mtu = htonl(mtu);
/* icmpv4 pptr is a one most significant byte */
if (ptr >= 0) {
icmp6->icmp6_pptr = htonl(ptr << 24);
}
break;
case AF_INET6:
icmp4 = arg;
type = icmp4->icmp_type;
code = icmp4->icmp_code;
mtu = ntohs(icmp4->icmp_nextmtu);
switch (type) {
case ICMP_ECHO:
type = ICMP6_ECHO_REQUEST;
break;
case ICMP_ECHOREPLY:
type = ICMP6_ECHO_REPLY;
break;
case ICMP_UNREACH:
type = ICMP6_DST_UNREACH;
switch (code) {
case ICMP_UNREACH_NET:
case ICMP_UNREACH_HOST:
case ICMP_UNREACH_NET_UNKNOWN:
case ICMP_UNREACH_HOST_UNKNOWN:
case ICMP_UNREACH_ISOLATED:
case ICMP_UNREACH_TOSNET:
case ICMP_UNREACH_TOSHOST:
code = ICMP6_DST_UNREACH_NOROUTE;
break;
case ICMP_UNREACH_PORT:
code = ICMP6_DST_UNREACH_NOPORT;
break;
case ICMP_UNREACH_NET_PROHIB:
case ICMP_UNREACH_HOST_PROHIB:
case ICMP_UNREACH_FILTER_PROHIB:
case ICMP_UNREACH_PRECEDENCE_CUTOFF:
code = ICMP6_DST_UNREACH_ADMIN;
break;
case ICMP_UNREACH_PROTOCOL:
type = ICMP6_PARAM_PROB;
code = ICMP6_PARAMPROB_NEXTHEADER;
ptr = offsetof(struct ip6_hdr, ip6_nxt);
break;
case ICMP_UNREACH_NEEDFRAG:
type = ICMP6_PACKET_TOO_BIG;
code = 0;
/*
* Make sure we don't overflow adjusting for
* translation overhead.
* If we do, just work with a lower mtu as is.
*/
if (mtu <= (UINT16_MAX - CLAT46_HDR_EXPANSION_OVERHD)) {
mtu += CLAT46_HDR_EXPANSION_OVERHD;
}
break;
default:
return -1;
}
break;
case ICMP_TIMXCEED:
type = ICMP6_TIME_EXCEEDED;
break;
case ICMP_PARAMPROB:
type = ICMP6_PARAM_PROB;
switch (code) {
case ICMP_PARAMPROB_ERRATPTR:
code = ICMP6_PARAMPROB_HEADER;
break;
case ICMP_PARAMPROB_LENGTH:
code = ICMP6_PARAMPROB_HEADER;
break;
default:
return -1;
}
ptr = icmp4->icmp_pptr;
if (ptr == 0 || ptr == PTR_IP(ip_tos)) {
; /* preserve */
} else if (ptr == PTR_IP(ip_len) ||
ptr == PTR_IP(ip_len) + 1) {
ptr = PTR_IP6(ip6_plen);
} else if (ptr == PTR_IP(ip_ttl)) {
ptr = PTR_IP6(ip6_hlim);
} else if (ptr == PTR_IP(ip_p)) {
ptr = PTR_IP6(ip6_nxt);
} else if (ptr >= PTR_IP(ip_src) &&
ptr < PTR_IP(ip_dst)) {
ptr = PTR_IP6(ip6_src);
} else if (ptr >= PTR_IP(ip_dst) &&
ptr < (int32_t)sizeof(struct ip)) {
ptr = PTR_IP6(ip6_dst);
} else {
return -1;
}
break;
default:
return -1;
}
icmp4->icmp_type = type;
icmp4->icmp_code = code;
icmp4->icmp_nextmtu = htons((uint16_t)mtu);
if (ptr >= 0) {
icmp4->icmp_void = htonl(ptr);
}
break;
}
return 0;
}
/*
* @brief This routine is called to perform address family translation on the
* inner IP header (that may come as payload) of an ICMP(v4/v6) error
* response.
*
* @param pbuf Pointer to packet buffer
* @param off Points to end of ICMP header
* @param tot_len Pointer to total length of the outer IP header
* @param off2 Points to end of inner IP header
* @param proto2 Inner IP proto field
* @param ttl2 Inner IP ttl field
* @param tot_len2 Inner IP total length
* @param src Pointer to the generic v4/v6 src address
* @param dst Pointer to the generic v4/v6 dst address
* @param af Old protocol family
* @param naf New protocol family
*
* @return -1 on error and 0 on success
*/
int
nat464_translate_icmp_ip(pbuf_t *pbuf, uint16_t off, uint16_t *tot_len, uint16_t *off2,
uint8_t proto2, uint8_t ttl2, uint16_t tot_len2, struct nat464_addr *src,
struct nat464_addr *dst, protocol_family_t af, protocol_family_t naf)
{
struct ip *ip4 = NULL;
struct ip6_hdr *ip6 = NULL;
void *hdr = NULL;
int hlen = 0, olen = 0;
uint64_t ipid_salt = (uint64_t)pbuf_get_packet_buffer_address(pbuf);
if (af == naf || (af != AF_INET && af != AF_INET6) ||
(naf != AF_INET && naf != AF_INET6)) {
return -1;
}
/* old header */
olen = *off2 - off;
/* new header */
hlen = naf == PF_INET ? sizeof(*ip4) : sizeof(*ip6);
/* Modify the pbuf to accommodate the new header */
hdr = pbuf_resize_segment(pbuf, off, olen, hlen);
if (hdr == NULL) {
return -1;
}
/* translate inner ip/ip6 header */
switch (naf) {
case AF_INET:
ip4 = hdr;
bzero(ip4, sizeof(*ip4));
ip4->ip_v = IPVERSION;
ip4->ip_hl = sizeof(*ip4) >> 2;
ip4->ip_len = htons((uint16_t)(sizeof(*ip4) + tot_len2 - olen));
ip4->ip_id = rfc6864 ? 0 : htons(ip_randomid(ipid_salt));
ip4->ip_off = htons(IP_DF);
ip4->ip_ttl = ttl2;
if (proto2 == IPPROTO_ICMPV6) {
ip4->ip_p = IPPROTO_ICMP;
} else {
ip4->ip_p = proto2;
}
ip4->ip_src = src->natv4addr;
ip4->ip_dst = dst->natv4addr;
ip4->ip_sum = pbuf_inet_cksum(pbuf, 0, 0, ip4->ip_hl << 2);
if (clat_debug) {
char buf[MAX_IPv4_STR_LEN];
clat_log2((LOG_DEBUG, "%s translated to IPv4 (inner) "
"ip_len: %#x ip_p: %d ip_sum: %#x ip_src: %s ip_dst: %s \n",
__func__, ntohs(ip4->ip_len), ip4->ip_p, ntohs(ip4->ip_sum),
inet_ntop(AF_INET, (void *)&ip4->ip_src, buf, sizeof(buf)),
inet_ntop(AF_INET, (void *)&ip4->ip_dst, buf, sizeof(buf))));
}
break;
case AF_INET6:
ip6 = hdr;
bzero(ip6, sizeof(*ip6));
ip6->ip6_vfc = IPV6_VERSION;
ip6->ip6_plen = htons((uint16_t)(tot_len2 - olen));
if (proto2 == IPPROTO_ICMP) {
ip6->ip6_nxt = IPPROTO_ICMPV6;
} else {
ip6->ip6_nxt = proto2;
}
if (!ttl2 || ttl2 > IPV6_DEFHLIM) {
ip6->ip6_hlim = IPV6_DEFHLIM;
} else {
ip6->ip6_hlim = ttl2;
}
ip6->ip6_src = src->natv6addr;
ip6->ip6_dst = dst->natv6addr;
if (clat_debug) {
char buf2[MAX_IPv6_STR_LEN];
clat_log2((LOG_DEBUG, "%s translated to IPv6 (inner) "
"ip6_plen: %#x ip6_nxt: %d ip6_src: %s ip6_dst: %s \n",
__func__, ntohs(ip6->ip6_plen), ip6->ip6_nxt,
inet_ntop(AF_INET6, (void *)&ip6->ip6_src, buf2, sizeof(buf2)),
inet_ntop(AF_INET6, (void *)&ip6->ip6_dst, buf2, sizeof(buf2))));
}
break;
}
/* adjust payload offset and total packet length */
*off2 += hlen - olen;
*tot_len += hlen - olen;
return 0;
}
/*
* @brief The function inserts IPv6 fragmentation header
* and populates it with the passed parameters.
*
* @param pbuf Pointer to the packet buffer
* @param ip_id IP identifier (in network byte order)
* @param frag_offset Fragment offset (in network byte order)
* @param is_last_frag Boolean indicating if the fragment header is for
* last fragment or not.
*
* @return -1 on error and 0 on success.
*/
int
nat464_insert_frag46(pbuf_t *pbuf, uint16_t ip_id_val, uint16_t frag_offset,
boolean_t is_last_frag)
{
struct ip6_frag *p_ip6_frag = NULL;
struct ip6_hdr *p_ip6h = NULL;
/* Insert IPv6 fragmentation header */
if (pbuf_resize_segment(pbuf, sizeof(struct ip6_hdr), 0,
sizeof(struct ip6_frag)) == NULL) {
return -1;
}
p_ip6h = mtod(pbuf->pb_mbuf, struct ip6_hdr *);
p_ip6_frag = (struct ip6_frag *)pbuf_contig_segment(pbuf,
sizeof(struct ip6_hdr), sizeof(struct ip6_frag));
if (p_ip6_frag == NULL) {
return -1;
}
/* Populate IPv6 fragmentation header */
p_ip6_frag->ip6f_nxt = p_ip6h->ip6_nxt;
p_ip6_frag->ip6f_reserved = 0;
p_ip6_frag->ip6f_offlg = (uint16_t)(frag_offset << 3);
if (!is_last_frag) {
p_ip6_frag->ip6f_offlg |= 0x1;
}
p_ip6_frag->ip6f_offlg = htons(p_ip6_frag->ip6f_offlg);
p_ip6_frag->ip6f_ident = ip_id_val;
/* Update IPv6 header */
p_ip6h->ip6_nxt = IPPROTO_FRAGMENT;
p_ip6h->ip6_plen = htons(ntohs(p_ip6h->ip6_plen) +
sizeof(struct ip6_frag));
return 0;
}
int
nat464_translate_64(pbuf_t *pbuf, int off, uint8_t tos,
uint8_t *proto, uint8_t ttl, struct in_addr src_v4,
struct in_addr dst_v4, uint64_t tot_len, boolean_t *p_is_first_frag)
{
struct ip *ip4;
struct ip6_frag *p_frag6 = NULL;
struct ip6_frag frag6 = {};
boolean_t is_frag = FALSE;
uint16_t ip_frag_off = 0;
/*
* ip_input asserts for rcvif to be not NULL
* That may not be true for two corner cases
* 1. If for some reason a local app sends DNS
* AAAA query to local host
* 2. If IPv6 stack in kernel internally generates a
* message destined for a synthesized IPv6 end-point.
*/
if (pbuf->pb_ifp == NULL) {
return NT_DROP;
}
if (*proto == IPPROTO_FRAGMENT) {
p_frag6 = (struct ip6_frag *)pbuf_contig_segment(pbuf,
sizeof(struct ip6_hdr), sizeof(struct ip6_frag));
if (p_frag6 == NULL) {
ip6stat.ip6s_clat464_in_64frag_transfail_drop++;
return NT_DROP;
}
frag6 = *p_frag6;
p_frag6 = NULL;
*proto = frag6.ip6f_nxt;
off += sizeof(struct ip6_frag);
is_frag = TRUE;
ip_frag_off = (ntohs(frag6.ip6f_offlg & IP6F_OFF_MASK)) >> 3;
if (ip_frag_off != 0) {
*p_is_first_frag = FALSE;
}
}
ip4 = (struct ip *)pbuf_resize_segment(pbuf, 0, off, sizeof(*ip4));
if (ip4 == NULL) {
return NT_DROP;
}
ip4->ip_v = 4;
ip4->ip_hl = 5;
ip4->ip_tos = tos;
ip4->ip_len = htons((uint16_t)(sizeof(*ip4) + (tot_len - off)));
ip4->ip_id = 0;
ip4->ip_off = 0;
ip4->ip_ttl = ttl;
ip4->ip_p = *proto;
ip4->ip_sum = 0;
ip4->ip_src = src_v4;
ip4->ip_dst = dst_v4;
if (is_frag) {
/*
* https://tools.ietf.org/html/rfc7915#section-5.1.1
* Identification: Copied from the low-order 16 bits in the
* Identification field in the Fragment Header.
*/
ip4->ip_id = ntohl(frag6.ip6f_ident) & 0xffff;
ip4->ip_id = htons(ip4->ip_id);
if (frag6.ip6f_offlg & IP6F_MORE_FRAG) {
ip_frag_off |= IP_MF;
}
ip4->ip_off = htons(ip_frag_off);
} else {
ip4->ip_off |= htons(IP_DF);
}
/*
* Defer calculating ip_sum for ICMPv6 as we do it
* later in Protocol translation
*/
if (*proto != IPPROTO_ICMPV6) {
ip4->ip_sum = pbuf_inet_cksum(pbuf, 0, 0, ip4->ip_hl << 2);
}
if (clat_debug) {
char buf1[MAX_IPv4_STR_LEN], buf2[MAX_IPv4_STR_LEN];
clat_log2((LOG_DEBUG, "%s translated to IPv4 ip_len: %#x "
"ip_p: %d ip_sum: %#x ip_src: %s ip_dst: %s \n", __func__,
ntohs(ip4->ip_len), ip4->ip_p, ntohs(ip4->ip_sum),
inet_ntop(AF_INET, (void *)&ip4->ip_src, buf1, sizeof(buf1)),
inet_ntop(AF_INET, (void *)&ip4->ip_dst, buf2, sizeof(buf2))));
}
return NT_NAT64;
}
/*
* @brief The routine translates the IPv4 header to IPv6 header.
*
* @param pbuf Pointer to the generic packet buffer
* @param off Offset to the end of IP header
* @param tos Type of service
* @param proto Protocol running over IP
* @param ttl Time to live
* @param src_v6 Source IPv6 address
* @param dst_v6 Destination IPv6 address
* @param tot_len Total payload length
*
* @return NT_NAT64 if IP header translation is successful, else error
*/
int
nat464_translate_46(pbuf_t *pbuf, uint16_t off, uint8_t tos,
uint8_t proto, uint8_t ttl, struct in6_addr src_v6,
struct in6_addr dst_v6, uint16_t tot_len)
{
struct ip6_hdr *ip6;
if (pbuf->pb_ifp == NULL) {
return NT_DROP;
}
/*
* Trim the buffer from head of size equal to to off (which is equal to
* the size of IP header and prepend IPv6 header length to the buffer
*/
ip6 = (struct ip6_hdr *)pbuf_resize_segment(pbuf, 0, off, sizeof(*ip6));
if (ip6 == NULL) {
return NT_DROP;
}
ip6->ip6_flow = htonl((6 << 28) | (tos << 20));
ip6->ip6_plen = htons(tot_len - off);
ip6->ip6_nxt = proto;
ip6->ip6_hlim = ttl;
ip6->ip6_src = src_v6;
ip6->ip6_dst = dst_v6;
if (clat_debug) {
char buf1[MAX_IPv6_STR_LEN], buf2[MAX_IPv6_STR_LEN];
clat_log2((LOG_DEBUG, "%s translated to IPv6 ip6_plen: %#x "
" ip6_nxt: %d ip6_src: %s ip6_dst: %s \n", __func__,
ntohs(ip6->ip6_plen), ip6->ip6_nxt,
inet_ntop(AF_INET6, (void *)&ip6->ip6_src, buf1, sizeof(buf1)),
inet_ntop(AF_INET6, (void *)&ip6->ip6_dst, buf2, sizeof(buf2))));
}
return NT_NAT64;
}
/* Handle the next protocol checksum */
/*
* @brief This routine translates the Proto running over IP and updates the checksum
* for IP header translation. It also updates pbuf checksum flags and related fields.
*
* @param pbuf Pointer to protocol buffer
* @param nsrc New source address
* @param ndst New destination address
* @param af Old family
* @param naf New family
*
* @return void
*/
int
nat464_translate_proto(pbuf_t *pbuf, struct nat464_addr *osrc,
struct nat464_addr *odst, uint8_t oproto, protocol_family_t af,
protocol_family_t naf, int direction, boolean_t only_csum)
{
struct ip *iph = NULL;
struct ip6_hdr *ip6h = NULL;
uint16_t hlen = 0, plen = 0;
uint16_t tot_len = 0;
void *nsrc = NULL, *ndst = NULL;
uint8_t *proto = 0;
uint16_t *psum = NULL;
boolean_t do_ones_complement = FALSE;
/* For now these routines only support 464 translations */
VERIFY(af != naf);
VERIFY(af == PF_INET || af == PF_INET6);
/*
* For now out must be for v4 to v6 translation
* and in must be for v6 to v4 translation.
*/
switch (naf) {
case PF_INET: {
iph = pbuf->pb_data;
hlen = (uint16_t)(iph->ip_hl << 2);
plen = ntohs(iph->ip_len) - hlen;
tot_len = ntohs(iph->ip_len);
nsrc = &iph->ip_src;
ndst = &iph->ip_dst;
proto = &iph->ip_p;
break;
}
case PF_INET6: {
ip6h = pbuf->pb_data;
hlen = (uint16_t)sizeof(*ip6h);
plen = ntohs(ip6h->ip6_plen);
tot_len = hlen + plen;
nsrc = &ip6h->ip6_src;
ndst = &ip6h->ip6_dst;
proto = &ip6h->ip6_nxt;
break;
}
default:
return NT_DROP; /* We should never come here */
}
if (*proto != oproto) {
return NT_DROP;
}
/*
* We may want to manipulate csum flags in some cases
* and not act on the protocol header as it may not
* carry protocol checksums.
* For example, fragments other than the first one would
* not carry protocol headers.
*/
if (only_csum) {
/*
* Only translate ICMP proto in the header
* and adjust checksums
*/
if (*proto == IPPROTO_ICMP) {
if (naf != PF_INET6) {
return NT_DROP;
}
*proto = IPPROTO_ICMPV6;
} else if (*proto == IPPROTO_ICMPV6) {
if (naf != PF_INET) {
return NT_DROP;
}
*proto = IPPROTO_ICMP;
/* Recalculate IP checksum as proto field has changed */
iph->ip_sum = 0;
iph->ip_sum = pbuf_inet_cksum(pbuf, 0, 0, hlen);
}
goto done;
}
switch (*proto) {
case IPPROTO_UDP: {
struct udphdr *uh = (struct udphdr *)pbuf_contig_segment(pbuf, hlen,
sizeof(*uh));
if (uh == NULL) {
return NT_DROP;
}
if (!(*pbuf->pb_csum_flags & (CSUM_UDP | CSUM_PARTIAL)) &&
uh->uh_sum == 0 && af == PF_INET && naf == PF_INET6) {
uh->uh_sum = pbuf_inet6_cksum(pbuf, IPPROTO_UDP,
hlen, ntohs(ip6h->ip6_plen));
if (uh->uh_sum == 0) {
uh->uh_sum = 0xffff;
}
goto done;
}
psum = &uh->uh_sum;
break;
}
case IPPROTO_TCP: {
struct tcphdr *th = (struct tcphdr *)pbuf_contig_segment(pbuf, hlen,
sizeof(*th));
if (th == NULL) {
return NT_DROP;
}
psum = &th->th_sum;
break;
}
}
/*
* Translate the protocol header, update IP header if needed,
* calculate checksums and update the checksum flags.
*/
switch (*proto) {
case IPPROTO_UDP:
/* Fall through */
case IPPROTO_TCP:
{
/*
* If it is a locally generated and has CSUM flags set
* for TCP and UDP it means we have pseudo header checksum
* that has not yet been one's complemented.
*/
if (direction == NT_OUT &&
(*pbuf->pb_csum_flags & CSUM_PARTIAL)) {
do_ones_complement = TRUE;
}
nat464_addr_cksum_fixup(psum, osrc, (struct nat464_addr *)nsrc,
af, naf, (*proto == IPPROTO_UDP) ? 1 : 0, do_ones_complement);
nat464_addr_cksum_fixup(psum, odst, (struct nat464_addr *)ndst,
af, naf, (*proto == IPPROTO_UDP) ? 1 : 0, do_ones_complement);
break;
}
case IPPROTO_ICMP: {
if (naf != PF_INET6) { /* allow only v6 as naf for ICMP */
return NT_DROP;
}
struct icmp *icmph = NULL;
struct icmp6_hdr *icmp6h = NULL;
uint16_t ip2off = 0, hlen2 = 0, tot_len2 = 0;
icmph = (struct icmp*) pbuf_contig_segment(pbuf, hlen,
ICMP_MINLEN);
if (icmph == NULL) {
return NT_DROP;
}
/* Translate the ICMP header */
if (nat464_translate_icmp(PF_INET6, icmph) != 0) {
return NT_DROP;
}
*proto = IPPROTO_ICMPV6;
icmp6h = (struct icmp6_hdr *)(uintptr_t)icmph;
pbuf_copy_back(pbuf, hlen, sizeof(struct icmp6_hdr),
icmp6h);
/*Translate the inner IP header only for error messages */
if (ICMP6_ERRORTYPE(icmp6h->icmp6_type)) {
ip2off = (uint16_t)(hlen + sizeof(*icmp6h));
struct ip *iph2 = NULL;
iph2 = (struct ip*) pbuf_contig_segment(pbuf, ip2off,
sizeof(*iph2));
if (iph2 == NULL) {
return NT_DROP;
}
hlen2 = (uint16_t)(ip2off + (iph2->ip_hl << 2));
tot_len2 = ntohs(iph2->ip_len);
/* Destination in outer IP should be Source in inner IP */
VERIFY(IN_ARE_ADDR_EQUAL(&odst->natv4addr, &iph2->ip_src));
if (nat464_translate_icmp_ip(pbuf, ip2off, &tot_len,
&hlen2, iph2->ip_p, iph2->ip_ttl, tot_len2,
(struct nat464_addr *)ndst, (struct nat464_addr *)nsrc,
PF_INET, PF_INET6) != 0) {
return NT_DROP;
}
/* Update total length/payload length for outer header */
switch (naf) {
case PF_INET:
iph->ip_len = htons(tot_len);
break;
case PF_INET6:
ip6h->ip6_plen = htons(tot_len - hlen);
break;
}
iph2 = NULL;
}
icmp6h->icmp6_cksum = 0;
icmp6h->icmp6_cksum = pbuf_inet6_cksum(pbuf, IPPROTO_ICMPV6, hlen,
ntohs(ip6h->ip6_plen));
clat_log2((LOG_DEBUG, "%s translated to ICMPV6 type: %d "
"code: %d checksum: %#x \n", __func__, icmp6h->icmp6_type,
icmp6h->icmp6_code, icmp6h->icmp6_cksum));
icmph = NULL;
icmp6h = NULL;
break;
}
case IPPROTO_ICMPV6:
{ if (naf != PF_INET) { /* allow only v4 as naf for ICMPV6 */
return NT_DROP;
}
struct icmp6_hdr *icmp6h = NULL;
struct icmp *icmph = NULL;
uint16_t ip2off = 0, hlen2 = 0, tot_len2 = 0;
icmp6h = (struct icmp6_hdr*) pbuf_contig_segment(pbuf, hlen,
sizeof(*icmp6h));
if (icmp6h == NULL) {
return NT_DROP;
}
/* Translate the ICMP header */
if (nat464_translate_icmp(PF_INET, icmp6h) != 0) {
return NT_DROP;
}
*proto = IPPROTO_ICMP;
icmph = (struct icmp *)(uintptr_t)icmp6h;
pbuf_copy_back(pbuf, hlen, ICMP_MINLEN,
icmph);
/*Translate the inner IP header only for error messages */
if (ICMP_ERRORTYPE(icmph->icmp_type)) {
ip2off = hlen + ICMP_MINLEN;
struct ip6_hdr *iph2 = NULL;
iph2 = (struct ip6_hdr*) pbuf_contig_segment(pbuf, ip2off,
sizeof(*iph2));
if (iph2 == NULL) {
return NT_DROP;
}
/* hlen2 points to end of inner IP header from the beginning */
hlen2 = ip2off + sizeof(struct ip6_hdr);
tot_len2 = ntohs(iph2->ip6_plen) + sizeof(struct ip6_hdr);
if (nat464_translate_icmp_ip(pbuf, ip2off, &tot_len,
&hlen2, iph2->ip6_nxt, iph2->ip6_hlim, tot_len2,
(struct nat464_addr *)ndst, (struct nat464_addr *)nsrc,
PF_INET6, PF_INET) != 0) {
return NT_DROP;
}
/* Update total length for outer header */
switch (naf) {
case PF_INET:
iph->ip_len = htons(tot_len);
break;
case PF_INET6:
ip6h->ip6_plen = htons(tot_len - hlen);
break;
}
iph2 = NULL;
}
/* Recalculate IP checksum as some IP fields might have changed */
iph->ip_sum = 0;
iph->ip_sum = pbuf_inet_cksum(pbuf, 0, 0, iph->ip_hl << 2);
icmph->icmp_cksum = 0;
icmph->icmp_cksum = pbuf_inet_cksum(pbuf, 0, hlen,
ntohs(iph->ip_len) - hlen);
clat_log2((LOG_DEBUG, "%s translated to ICMP type: %d "
"code: %d checksum: %#x \n", __func__, icmph->icmp_type,
icmph->icmp_code, icmph->icmp_cksum));
icmp6h = NULL;
icmph = NULL;
break;}
/*
* https://tools.ietf.org/html/rfc7915#section-5.1.1
* If the Next Header field of the Fragment Header is an
* extension header (except ESP, but including the Authentication
* Header (AH)), then the packet SHOULD be dropped and logged.
*/
case IPPROTO_HOPOPTS:
case IPPROTO_ROUTING:
case IPPROTO_DSTOPTS:
case IPPROTO_AH:
return NT_DROP;
case IPPROTO_FRAGMENT:
/*
* The fragment header is appended after or removed before
* calling into this routine.
*/
VERIFY(FALSE);
case IPPROTO_ESP:
break;
default:
return NT_DROP;
}
done:
/* Update checksum flags and offsets based on direction */
if (direction == NT_OUT) {
if ((*pbuf->pb_csum_flags & (CSUM_DATA_VALID | CSUM_PARTIAL)) ==
(CSUM_DATA_VALID | CSUM_PARTIAL)) {
(pbuf->pb_mbuf)->m_pkthdr.csum_tx_start += CLAT46_HDR_EXPANSION_OVERHD;
(pbuf->pb_mbuf)->m_pkthdr.csum_tx_stuff += CLAT46_HDR_EXPANSION_OVERHD;
}
if (*pbuf->pb_csum_flags & CSUM_TCP) {
*pbuf->pb_csum_flags |= CSUM_TCPIPV6;
}
if (*pbuf->pb_csum_flags & CSUM_UDP) {
*pbuf->pb_csum_flags |= CSUM_UDPIPV6;
}
if (*pbuf->pb_csum_flags & CSUM_FRAGMENT) {
*pbuf->pb_csum_flags |= CSUM_FRAGMENT_IPV6;
}
/* Clear IPv4 checksum flags */
*pbuf->pb_csum_flags &= ~(CSUM_IP | CSUM_IP_FRAGS | CSUM_DELAY_DATA | CSUM_FRAGMENT);
/*
* If the packet requires TCP segmentation due to TSO offload,
* then change the checksum flag to indicate that an IPv6
* TCP segmentation is needed now.
*/
if (*pbuf->pb_csum_flags & CSUM_TSO_IPV4) {
*pbuf->pb_csum_flags &= ~CSUM_TSO_IPV4;
*pbuf->pb_csum_flags |= CSUM_TSO_IPV6;
}
} else if (direction == NT_IN) {
/* XXX On input just reset csum flags */
*pbuf->pb_csum_flags = 0; /* Reset all flags for now */
#if 0
/* Update csum flags and offsets for rx */
if (*pbuf->pb_csum_flags & CSUM_PARTIAL) {
(pbuf->pb_mbuf)->m_pkthdr.csum_rx_start -= CLAT46_HDR_EXPANSION_OVERHD;
}
#endif
}
return NT_NAT64;
}
/* Fix the proto checksum for address change */
static void
nat464_addr_cksum_fixup(uint16_t *pc, struct nat464_addr *ao, struct nat464_addr *an,
protocol_family_t af, protocol_family_t naf, uint8_t u, boolean_t do_ones_complement)
{
/* Currently we only support v4 to v6 and vice versa */
VERIFY(af != naf);
switch (af) {
case PF_INET:
switch (naf) {
case PF_INET6:
if (do_ones_complement) {
*pc = ~nat464_cksum_fixup(nat464_cksum_fixup(
nat464_cksum_fixup(nat464_cksum_fixup(nat464_cksum_fixup(
nat464_cksum_fixup(nat464_cksum_fixup(nat464_cksum_fixup(~*pc,
ao->nataddr16[0], an->nataddr16[0], u),
ao->nataddr16[1], an->nataddr16[1], u),
0, an->nataddr16[2], u),
0, an->nataddr16[3], u),
0, an->nataddr16[4], u),
0, an->nataddr16[5], u),
0, an->nataddr16[6], u),
0, an->nataddr16[7], u);
} else {
*pc = nat464_cksum_fixup(nat464_cksum_fixup(
nat464_cksum_fixup(nat464_cksum_fixup(nat464_cksum_fixup(
nat464_cksum_fixup(nat464_cksum_fixup(nat464_cksum_fixup(*pc,
ao->nataddr16[0], an->nataddr16[0], u),
ao->nataddr16[1], an->nataddr16[1], u),
0, an->nataddr16[2], u),
0, an->nataddr16[3], u),
0, an->nataddr16[4], u),
0, an->nataddr16[5], u),
0, an->nataddr16[6], u),
0, an->nataddr16[7], u);
}
break;
}
break;
case PF_INET6:
/*
* XXX For NAT464 this only applies to the incoming path.
* The checksum therefore is already ones complemented.
* Therefore we just perform normal fixup.
*/
switch (naf) {
case PF_INET:
*pc = nat464_cksum_fixup(nat464_cksum_fixup(
nat464_cksum_fixup(nat464_cksum_fixup(nat464_cksum_fixup(
nat464_cksum_fixup(nat464_cksum_fixup(nat464_cksum_fixup(*pc,
ao->nataddr16[0], an->nataddr16[0], u),
ao->nataddr16[1], an->nataddr16[1], u),
ao->nataddr16[2], 0, u),
ao->nataddr16[3], 0, u),
ao->nataddr16[4], 0, u),
ao->nataddr16[5], 0, u),
ao->nataddr16[6], 0, u),
ao->nataddr16[7], 0, u);
break;
}
break;
}
}
uint16_t
nat464_cksum_fixup(uint16_t cksum, uint16_t old, uint16_t new, uint8_t udp)
{
uint32_t l;
if (udp && !cksum) {
return 0;
}
l = cksum + old - new;
l = (l >> 16) + (l & 0xffff);
l = l & 0xffff;
if (udp && !l) {
return 0xffff;
}
return (uint16_t)l;
}
/* CLAT46 event handlers */
void
in6_clat46_eventhdlr_callback(struct eventhandler_entry_arg arg0 __unused,
in6_clat46_evhdlr_code_t in6_clat46_ev_code, pid_t epid, uuid_t euuid)
{
struct kev_msg ev_msg;
struct kev_netevent_clat46_data clat46_event_data;
bzero(&ev_msg, sizeof(ev_msg));
bzero(&clat46_event_data, sizeof(clat46_event_data));
ev_msg.vendor_code = KEV_VENDOR_APPLE;
ev_msg.kev_class = KEV_NETWORK_CLASS;
ev_msg.kev_subclass = KEV_NETEVENT_SUBCLASS;
ev_msg.event_code = KEV_NETEVENT_CLAT46_EVENT;
bzero(&clat46_event_data, sizeof(clat46_event_data));
clat46_event_data.clat46_event_code = in6_clat46_ev_code;
clat46_event_data.epid = epid;
uuid_copy(clat46_event_data.euuid, euuid);
ev_msg.dv[0].data_ptr = &clat46_event_data;
ev_msg.dv[0].data_length = sizeof(clat46_event_data);
kev_post_msg(&ev_msg);
}
struct in6_clat46_event_nwk_wq_entry {
struct nwk_wq_entry nwk_wqe;
struct kev_netevent_clat46_data in6_clat46_ev_arg;
};
static void
in6_clat46_event_callback(struct nwk_wq_entry *nwk_item)
{
struct in6_clat46_event_nwk_wq_entry *p_ev;
p_ev = __container_of(nwk_item,
struct in6_clat46_event_nwk_wq_entry, nwk_wqe);
EVENTHANDLER_INVOKE(&in6_clat46_evhdlr_ctxt, in6_clat46_event,
p_ev->in6_clat46_ev_arg.clat46_event_code, p_ev->in6_clat46_ev_arg.epid,
p_ev->in6_clat46_ev_arg.euuid);
kfree_type(struct in6_clat46_event_nwk_wq_entry, p_ev);
}
void
in6_clat46_event_enqueue_nwk_wq_entry(in6_clat46_evhdlr_code_t in6_clat46_event_code,
pid_t epid, uuid_t euuid)
{
struct in6_clat46_event_nwk_wq_entry *p_ev = NULL;
p_ev = kalloc_type(struct in6_clat46_event_nwk_wq_entry,
Z_WAITOK | Z_ZERO | Z_NOFAIL);
p_ev->nwk_wqe.func = in6_clat46_event_callback;
p_ev->in6_clat46_ev_arg.clat46_event_code = in6_clat46_event_code;
p_ev->in6_clat46_ev_arg.epid = epid;
uuid_copy(p_ev->in6_clat46_ev_arg.euuid, euuid);
nwk_wq_enqueue(&p_ev->nwk_wqe);
}
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