diff options
Diffstat (limited to 'src/VBox/NetworkServices/NAT/pxping.c')
| -rw-r--r-- | src/VBox/NetworkServices/NAT/pxping.c | 2020 |
1 files changed, 2020 insertions, 0 deletions
diff --git a/src/VBox/NetworkServices/NAT/pxping.c b/src/VBox/NetworkServices/NAT/pxping.c new file mode 100644 index 00000000..9acee074 --- /dev/null +++ b/src/VBox/NetworkServices/NAT/pxping.c @@ -0,0 +1,2020 @@ +/* $Id: pxping.c $ */ +/** @file + * NAT Network - ping proxy, raw sockets version. + */ + +/* + * Copyright (C) 2013-2023 Oracle and/or its affiliates. + * + * This file is part of VirtualBox base platform packages, as + * available from https://www.virtualbox.org. + * + * 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, in version 3 of the + * License. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, see <https://www.gnu.org/licenses>. + * + * SPDX-License-Identifier: GPL-3.0-only + */ + +#define LOG_GROUP LOG_GROUP_NAT_SERVICE + +#include "winutils.h" +#include "proxy.h" +#include "proxy_pollmgr.h" +#include "pxremap.h" + +#include <iprt/string.h> + +#ifndef RT_OS_WINDOWS +#include <sys/types.h> +#include <sys/socket.h> +#ifdef RT_OS_DARWIN +# define __APPLE_USE_RFC_3542 +#endif +#include <netinet/in.h> +#include <poll.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#else +#include <iprt/stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include "winpoll.h" +#endif + +#include "lwip/opt.h" + +#include "lwip/sys.h" +#include "lwip/tcpip.h" +#include "lwip/inet_chksum.h" +#include "lwip/ip.h" +#include "lwip/icmp.h" + +#if defined(RT_OS_LINUX) && !defined(__USE_GNU) +#if __GLIBC_PREREQ(2, 8) +/* + * XXX: This is gross. in6_pktinfo is now hidden behind _GNU_SOURCE + * https://sourceware.org/bugzilla/show_bug.cgi?id=6775 + * + * But in older glibc versions, e.g. RHEL5, it is not! I don't want + * to deal with _GNU_SOURCE now, so as a kludge check for glibc + * version. It seems the __USE_GNU guard was introduced in 2.8. + */ +struct in6_pktinfo { + struct in6_addr ipi6_addr; + unsigned int ipi6_ifindex; +}; +#endif /* __GLIBC_PREREQ */ +#endif /* RT_OS_LINUX && !__USE_GNU */ + + +/* forward */ +struct ping_pcb; + + +/** + * Global state for ping proxy collected in one entity to minimize + * globals. There's only one instance of this structure. + * + * Raw ICMP sockets are promiscuous, so it doesn't make sense to have + * multiple. If this code ever needs to support multiple netifs, the + * netif member should be exiled into "pcb". + */ +struct pxping { + SOCKET sock4; + +#if defined(RT_OS_DARWIN) || defined(RT_OS_SOLARIS) +# define DF_WITH_IP_HDRINCL + int hdrincl; +#else + int df; +#endif + int ttl; + int tos; + + SOCKET sock6; +#ifdef RT_OS_WINDOWS + LPFN_WSARECVMSG pfWSARecvMsg6; +#endif + int hopl; + + struct pollmgr_handler pmhdl4; + struct pollmgr_handler pmhdl6; + + struct netif *netif; + + /** + * Protect lwIP and pmgr accesses to the list of pcbs. + */ + sys_mutex_t lock; + + /* + * We need to find pcbs both from the guest side and from the host + * side. If we need to support industrial grade ping throughput, + * we will need two pcb hashes. For now, a short linked list + * should be enough. Cf. pxping_pcb_for_request() and + * pxping_pcb_for_reply(). + */ +#define PXPING_MAX_PCBS 8 + size_t npcbs; + struct ping_pcb *pcbs; + +#define TIMEOUT 5 + int timer_active; + size_t timeout_slot; + struct ping_pcb *timeout_list[TIMEOUT]; +}; + + +/** + * Quasi PCB for ping. + */ +struct ping_pcb { + ipX_addr_t src; + ipX_addr_t dst; + + u8_t is_ipv6; + u8_t is_mapped; + + u16_t guest_id; + u16_t host_id; + + /** + * Desired slot in pxping::timeout_list. See pxping_timer(). + */ + size_t timeout_slot; + + /** + * Chaining for pxping::timeout_list + */ + struct ping_pcb **pprev_timeout; + struct ping_pcb *next_timeout; + + /** + * Chaining for pxping::pcbs + */ + struct ping_pcb *next; + + union { + struct sockaddr_in sin; + struct sockaddr_in6 sin6; + } peer; +}; + + +/** + * lwIP thread callback message for IPv4 ping. + * + * We pass raw IP datagram for ip_output_if() so we only need pbuf and + * netif (from pxping). + */ +struct ping_msg { + struct tcpip_msg msg; + struct pxping *pxping; + struct pbuf *p; +}; + + +/** + * lwIP thread callback message for IPv6 ping. + * + * We cannot obtain raw IPv6 datagram from host without extra trouble, + * so we pass ICMPv6 payload in pbuf and also other parameters to + * ip6_output_if(). + */ +struct ping6_msg { + struct tcpip_msg msg; + struct pxping *pxping; + struct pbuf *p; + ip6_addr_t src, dst; + int hopl, tclass; +}; + + +#ifdef RT_OS_WINDOWS +static int pxping_init_windows(struct pxping *pxping); +#endif +static void pxping_recv4(void *arg, struct pbuf *p); +static void pxping_recv6(void *arg, struct pbuf *p); + +static void pxping_timer(void *arg); +static void pxping_timer_needed(struct pxping *pxping); + +static struct ping_pcb *pxping_pcb_for_request(struct pxping *pxping, + int is_ipv6, + ipX_addr_t *src, ipX_addr_t *dst, + u16_t guest_id); +static struct ping_pcb *pxping_pcb_for_reply(struct pxping *pxping, int is_ipv6, + ipX_addr_t *dst, u16_t host_id); + +static FNRTSTRFORMATTYPE pxping_pcb_rtstrfmt; +static struct ping_pcb *pxping_pcb_allocate(struct pxping *pxping); +static void pxping_pcb_register(struct pxping *pxping, struct ping_pcb *pcb); +static void pxping_pcb_deregister(struct pxping *pxping, struct ping_pcb *pcb); +static void pxping_pcb_delete(struct pxping *pxping, struct ping_pcb *pcb); +static void pxping_timeout_add(struct pxping *pxping, struct ping_pcb *pcb); +static void pxping_timeout_del(struct pxping *pxping, struct ping_pcb *pcb); + +static int pxping_pmgr_pump(struct pollmgr_handler *handler, SOCKET fd, int revents); + +static void pxping_pmgr_icmp4(struct pxping *pxping); +static void pxping_pmgr_icmp4_echo(struct pxping *pxping, + u16_t iplen, struct sockaddr_in *peer); +static void pxping_pmgr_icmp4_error(struct pxping *pxping, + u16_t iplen, struct sockaddr_in *peer); +static void pxping_pmgr_icmp6(struct pxping *pxping); +static void pxping_pmgr_icmp6_echo(struct pxping *pxping, + ip6_addr_t *src, ip6_addr_t *dst, + int hopl, int tclass, u16_t icmplen); +static void pxping_pmgr_icmp6_error(struct pxping *pxping, + ip6_addr_t *src, ip6_addr_t *dst, + int hopl, int tclass, u16_t icmplen); + +static void pxping_pmgr_forward_inbound(struct pxping *pxping, u16_t iplen); +static void pxping_pcb_forward_inbound(void *arg); + +static void pxping_pmgr_forward_inbound6(struct pxping *pxping, + ip6_addr_t *src, ip6_addr_t *dst, + u8_t hopl, u8_t tclass, + u16_t icmplen); +static void pxping_pcb_forward_inbound6(void *arg); + +/* + * NB: This is not documented except in RTFS. + * + * If ip_output_if() is passed dest == NULL then it treats p as + * complete IP packet with payload pointing to the IP header. It does + * not build IP header, ignores all header-related arguments, fetches + * real destination from the header in the pbuf and outputs pbuf to + * the specified netif. + */ +#define ip_raw_output_if(p, netif) \ + (ip_output_if((p), NULL, NULL, 0, 0, 0, (netif))) + + + +static struct pxping g_pxping; + + +err_t +pxping_init(struct netif *netif, SOCKET sock4, SOCKET sock6) +{ + const int on = 1; + int status; + + if (sock4 == INVALID_SOCKET && sock6 == INVALID_SOCKET) { + return ERR_VAL; + } + + g_pxping.netif = netif; + sys_mutex_new(&g_pxping.lock); + + g_pxping.sock4 = sock4; + if (g_pxping.sock4 != INVALID_SOCKET) { +#ifdef DF_WITH_IP_HDRINCL + g_pxping.hdrincl = 0; +#else + g_pxping.df = -1; +#endif + g_pxping.ttl = -1; + g_pxping.tos = 0; + +#ifdef RT_OS_LINUX + { + const int dont = IP_PMTUDISC_DONT; + status = setsockopt(sock4, IPPROTO_IP, IP_MTU_DISCOVER, + &dont, sizeof(dont)); + if (status != 0) { + DPRINTF(("IP_MTU_DISCOVER: %R[sockerr]\n", SOCKERRNO())); + } + } +#endif /* RT_OS_LINUX */ + + g_pxping.pmhdl4.callback = pxping_pmgr_pump; + g_pxping.pmhdl4.data = (void *)&g_pxping; + g_pxping.pmhdl4.slot = -1; + pollmgr_add(&g_pxping.pmhdl4, g_pxping.sock4, POLLIN); + + ping_proxy_accept(pxping_recv4, &g_pxping); + } + + g_pxping.sock6 = sock6; +#ifdef RT_OS_WINDOWS + /* we need recvmsg */ + if (g_pxping.sock6 != INVALID_SOCKET) { + status = pxping_init_windows(&g_pxping); + if (status == SOCKET_ERROR) { + g_pxping.sock6 = INVALID_SOCKET; + /* close(sock6); */ + } + } +#endif + if (g_pxping.sock6 != INVALID_SOCKET) { + g_pxping.hopl = -1; + +#if !defined(IPV6_RECVPKTINFO) +#define IPV6_RECVPKTINFO (IPV6_PKTINFO) +#endif + status = setsockopt(sock6, IPPROTO_IPV6, IPV6_RECVPKTINFO, + (const char *)&on, sizeof(on)); + if (status < 0) { + DPRINTF(("IPV6_RECVPKTINFO: %R[sockerr]\n", SOCKERRNO())); + /* XXX: for now this is fatal */ + } + +#if !defined(IPV6_RECVHOPLIMIT) +#define IPV6_RECVHOPLIMIT (IPV6_HOPLIMIT) +#endif + status = setsockopt(sock6, IPPROTO_IPV6, IPV6_RECVHOPLIMIT, + (const char *)&on, sizeof(on)); + if (status < 0) { + DPRINTF(("IPV6_RECVHOPLIMIT: %R[sockerr]\n", SOCKERRNO())); + } + +#ifdef IPV6_RECVTCLASS /* new in RFC 3542, there's no RFC 2292 counterpart */ + /** @todo IPV6_RECVTCLASS */ +#endif + + g_pxping.pmhdl6.callback = pxping_pmgr_pump; + g_pxping.pmhdl6.data = (void *)&g_pxping; + g_pxping.pmhdl6.slot = -1; + pollmgr_add(&g_pxping.pmhdl6, g_pxping.sock6, POLLIN); + + ping6_proxy_accept(pxping_recv6, &g_pxping); + } + + status = RTStrFormatTypeRegister("ping_pcb", pxping_pcb_rtstrfmt, NULL); + AssertRC(status); + + return ERR_OK; +} + + +#ifdef RT_OS_WINDOWS +static int +pxping_init_windows(struct pxping *pxping) +{ + GUID WSARecvMsgGUID = WSAID_WSARECVMSG; + DWORD nread; + int status; + + pxping->pfWSARecvMsg6 = NULL; + status = WSAIoctl(pxping->sock6, + SIO_GET_EXTENSION_FUNCTION_POINTER, + &WSARecvMsgGUID, sizeof(WSARecvMsgGUID), + &pxping->pfWSARecvMsg6, sizeof(pxping->pfWSARecvMsg6), + &nread, + NULL, NULL); + return status; +} +#endif /* RT_OS_WINDOWS */ + + +static u32_t +chksum_delta_16(u16_t oval, u16_t nval) +{ + u32_t sum = (u16_t)~oval; + sum += nval; + return sum; +} + + +static u32_t +chksum_update_16(u16_t *oldp, u16_t nval) +{ + u32_t sum = chksum_delta_16(*oldp, nval); + *oldp = nval; + return sum; +} + + +static u32_t +chksum_delta_32(u32_t oval, u32_t nval) +{ + u32_t sum = ~oval; + sum = FOLD_U32T(sum); + sum += FOLD_U32T(nval); + return sum; +} + + +static u32_t +chksum_update_32(u32_t *oldp, u32_t nval) +{ + u32_t sum = chksum_delta_32(*oldp, nval); + *oldp = nval; + return sum; +} + + +static u32_t +chksum_delta_ipv6(const ip6_addr_t *oldp, const ip6_addr_t *newp) +{ + u32_t sum; + + sum = chksum_delta_32(oldp->addr[0], newp->addr[0]); + sum += chksum_delta_32(oldp->addr[1], newp->addr[1]); + sum += chksum_delta_32(oldp->addr[2], newp->addr[2]); + sum += chksum_delta_32(oldp->addr[3], newp->addr[3]); + + return sum; +} + + +static u32_t +chksum_update_ipv6(ip6_addr_t *oldp, const ip6_addr_t *newp) +{ + u32_t sum; + + sum = chksum_update_32(&oldp->addr[0], newp->addr[0]); + sum += chksum_update_32(&oldp->addr[1], newp->addr[1]); + sum += chksum_update_32(&oldp->addr[2], newp->addr[2]); + sum += chksum_update_32(&oldp->addr[3], newp->addr[3]); + + return sum; +} + + +/** + * ICMP Echo Request in pbuf "p" is to be proxied. + */ +static void +pxping_recv4(void *arg, struct pbuf *p) +{ + struct pxping *pxping = (struct pxping *)arg; + struct ping_pcb *pcb; +#ifdef DF_WITH_IP_HDRINCL + struct ip_hdr iph_orig; +#endif + struct icmp_echo_hdr icmph_orig; + struct ip_hdr *iph; + struct icmp_echo_hdr *icmph; + int df, ttl, tos; + u32_t sum; + u16_t iphlen; + int status; + + iphlen = ip_current_header_tot_len(); + if (iphlen != IP_HLEN) { /* we don't do options */ + pbuf_free(p); + return; + } + + iph = (/* UNCONST */ struct ip_hdr *)ip_current_header(); + icmph = (struct icmp_echo_hdr *)p->payload; + + pcb = pxping_pcb_for_request(pxping, 0, + ipX_current_src_addr(), + ipX_current_dest_addr(), + icmph->id); + if (pcb == NULL) { + pbuf_free(p); + return; + } + + DPRINTF(("ping %p: %R[ping_pcb] seq %d len %u ttl %d\n", + pcb, pcb, + ntohs(icmph->seqno), (unsigned int)p->tot_len, + IPH_TTL(iph))); + + ttl = IPH_TTL(iph); + if (!pcb->is_mapped) { + if (RT_UNLIKELY(ttl == 1)) { + status = pbuf_header(p, iphlen); /* back to IP header */ + if (RT_LIKELY(status == 0)) { + icmp_time_exceeded(p, ICMP_TE_TTL); + } + pbuf_free(p); + return; + } + --ttl; + } + + /* + * OS X doesn't provide a socket option to control fragmentation. + * Solaris doesn't provide IP_DONTFRAG on all releases we support. + * In this case we have to use IP_HDRINCL. We don't want to use + * it always since it doesn't handle fragmentation (but that's ok + * for DF) and Windows doesn't do automatic source address + * selection with IP_HDRINCL. + */ + df = (IPH_OFFSET(iph) & PP_HTONS(IP_DF)) != 0; + +#ifdef DF_WITH_IP_HDRINCL + if (df != pxping->hdrincl) { + status = setsockopt(pxping->sock4, IPPROTO_IP, IP_HDRINCL, + &df, sizeof(df)); + if (RT_LIKELY(status == 0)) { + pxping->hdrincl = df; + } + else { + DPRINTF(("IP_HDRINCL: %R[sockerr]\n", SOCKERRNO())); + } + } + + if (pxping->hdrincl) { + status = pbuf_header(p, iphlen); /* back to IP header */ + if (RT_UNLIKELY(status != 0)) { + pbuf_free(p); + return; + } + + /* we will overwrite IP header, save original for ICMP errors */ + memcpy(&iph_orig, iph, iphlen); + + if (pcb->is_mapped) { + ip4_addr_set_u32(&iph->dest, pcb->peer.sin.sin_addr.s_addr); + } + + if (g_proxy_options->src4 != NULL) { + ip4_addr_set_u32(&iph->src, g_proxy_options->src4->sin_addr.s_addr); + } + else { + /* let the kernel select suitable source address */ + ip_addr_set_any(&iph->src); + } + + IPH_TTL_SET(iph, ttl); /* already decremented */ + IPH_ID_SET(iph, 0); /* kernel will set one */ +#ifdef RT_OS_DARWIN + /* wants ip_offset and ip_len fields in host order */ + IPH_OFFSET_SET(iph, ntohs(IPH_OFFSET(iph))); + IPH_LEN_SET(iph, ntohs(IPH_LEN(iph))); + /* wants checksum of everything (sic!), in host order */ + sum = inet_chksum_pbuf(p); + IPH_CHKSUM_SET(iph, sum); +#else /* !RT_OS_DARWIN */ + IPH_CHKSUM_SET(iph, 0); /* kernel will recalculate */ +#endif + } + else /* !pxping->hdrincl */ +#endif /* DF_WITH_IP_HDRINCL */ + { +#if !defined(DF_WITH_IP_HDRINCL) + /* control DF flag via setsockopt(2) */ +#define USE_DF_OPTION(_Optname) \ + const int dfopt = _Optname; \ + const char * const dfoptname = #_Optname; NOREF(dfoptname) +#if defined(RT_OS_LINUX) + USE_DF_OPTION(IP_MTU_DISCOVER); + df = df ? IP_PMTUDISC_DO : IP_PMTUDISC_DONT; +#elif defined(RT_OS_SOLARIS) || defined(RT_OS_FREEBSD) + USE_DF_OPTION(IP_DONTFRAG); +#elif defined(RT_OS_WINDOWS) + USE_DF_OPTION(IP_DONTFRAGMENT); +#endif + if (df != pxping->df) { + status = setsockopt(pxping->sock4, IPPROTO_IP, dfopt, + (char *)&df, sizeof(df)); + if (RT_LIKELY(status == 0)) { + pxping->df = df; + } + else { + DPRINTF(("%s: %R[sockerr]\n", dfoptname, SOCKERRNO())); + } + } +#endif /* !DF_WITH_IP_HDRINCL */ + + if (ttl != pxping->ttl) { + status = setsockopt(pxping->sock4, IPPROTO_IP, IP_TTL, + (char *)&ttl, sizeof(ttl)); + if (RT_LIKELY(status == 0)) { + pxping->ttl = ttl; + } + else { + DPRINTF(("IP_TTL: %R[sockerr]\n", SOCKERRNO())); + } + } + + tos = IPH_TOS(iph); + if (tos != pxping->tos) { + status = setsockopt(pxping->sock4, IPPROTO_IP, IP_TOS, + (char *)&tos, sizeof(tos)); + if (RT_LIKELY(status == 0)) { + pxping->tos = tos; + } + else { + DPRINTF(("IP_TOS: %R[sockerr]\n", SOCKERRNO())); + } + } + } + + /* rewrite ICMP echo header */ + memcpy(&icmph_orig, icmph, sizeof(*icmph)); + sum = (u16_t)~icmph->chksum; + sum += chksum_update_16(&icmph->id, pcb->host_id); + sum = FOLD_U32T(sum); + icmph->chksum = ~sum; + + status = proxy_sendto(pxping->sock4, p, + &pcb->peer.sin, sizeof(pcb->peer.sin)); + if (status != 0) { + int error = -status; + DPRINTF(("%s: sendto: %R[sockerr]\n", __func__, error)); + +#ifdef DF_WITH_IP_HDRINCL + if (pxping->hdrincl) { + /* restore original IP header */ + memcpy(iph, &iph_orig, iphlen); + } + else +#endif + { + status = pbuf_header(p, iphlen); /* back to IP header */ + if (RT_UNLIKELY(status != 0)) { + pbuf_free(p); + return; + } + } + + /* restore original ICMP header */ + memcpy(icmph, &icmph_orig, sizeof(*icmph)); + + /* + * Some ICMP errors may be generated by the kernel and we read + * them from the socket and forward them normally, hence the + * ifdefs below. + */ + switch (error) { + +#if !( defined(RT_OS_SOLARIS) \ + || (defined(RT_OS_LINUX) && !defined(DF_WITH_IP_HDRINCL)) \ + ) + case EMSGSIZE: + icmp_dest_unreach(p, ICMP_DUR_FRAG); + break; +#endif + + case ENETDOWN: + case ENETUNREACH: + icmp_dest_unreach(p, ICMP_DUR_NET); + break; + + case EHOSTDOWN: + case EHOSTUNREACH: + icmp_dest_unreach(p, ICMP_DUR_HOST); + break; + } + } + + pbuf_free(p); +} + + +/** + * ICMPv6 Echo Request in pbuf "p" is to be proxied. + */ +static void +pxping_recv6(void *arg, struct pbuf *p) +{ + struct pxping *pxping = (struct pxping *)arg; + struct ping_pcb *pcb; + struct ip6_hdr *iph; + struct icmp6_echo_hdr *icmph; + int hopl; + u16_t iphlen; + u16_t id, seq; + int status; + + iph = (/* UNCONST */ struct ip6_hdr *)ip6_current_header(); + iphlen = ip_current_header_tot_len(); + + icmph = (struct icmp6_echo_hdr *)p->payload; + + id = icmph->id; + seq = icmph->seqno; + + pcb = pxping_pcb_for_request(pxping, 1, + ipX_current_src_addr(), + ipX_current_dest_addr(), + id); + if (pcb == NULL) { + pbuf_free(p); + return; + } + + DPRINTF(("ping %p: %R[ping_pcb] seq %d len %u hopl %d\n", + pcb, pcb, + ntohs(seq), (unsigned int)p->tot_len, + IP6H_HOPLIM(iph))); + + hopl = IP6H_HOPLIM(iph); + if (!pcb->is_mapped) { + if (hopl == 1) { + status = pbuf_header(p, iphlen); /* back to IP header */ + if (RT_LIKELY(status == 0)) { + icmp6_time_exceeded(p, ICMP6_TE_HL); + } + pbuf_free(p); + return; + } + --hopl; + } + + /* + * Rewrite ICMPv6 echo header. We don't need to recompute the + * checksum since, unlike IPv4, checksum includes pseudo-header. + * OS computes checksum for us on send() since it needs to select + * source address. + */ + icmph->id = pcb->host_id; + + /** @todo use control messages to save a syscall? */ + if (hopl != pxping->hopl) { + status = setsockopt(pxping->sock6, IPPROTO_IPV6, IPV6_UNICAST_HOPS, + (char *)&hopl, sizeof(hopl)); + if (status == 0) { + pxping->hopl = hopl; + } + else { + DPRINTF(("IPV6_HOPLIMIT: %R[sockerr]\n", SOCKERRNO())); + } + } + + status = proxy_sendto(pxping->sock6, p, + &pcb->peer.sin6, sizeof(pcb->peer.sin6)); + if (status != 0) { + int error = -status; + DPRINTF(("%s: sendto: %R[sockerr]\n", __func__, error)); + + status = pbuf_header(p, iphlen); /* back to IP header */ + if (RT_UNLIKELY(status != 0)) { + pbuf_free(p); + return; + } + + /* restore original ICMP header */ + icmph->id = pcb->guest_id; + + switch (error) { + case EACCES: + icmp6_dest_unreach(p, ICMP6_DUR_PROHIBITED); + break; + +#ifdef ENONET + case ENONET: +#endif + case ENETDOWN: + case ENETUNREACH: + case EHOSTDOWN: + case EHOSTUNREACH: + icmp6_dest_unreach(p, ICMP6_DUR_NO_ROUTE); + break; + } + } + + pbuf_free(p); +} + + +/** + * Formatter for %R[ping_pcb]. + */ +static DECLCALLBACK(size_t) +pxping_pcb_rtstrfmt(PFNRTSTROUTPUT pfnOutput, void *pvArgOutput, + const char *pszType, const void *pvValue, + int cchWidth, int cchPrecision, unsigned int fFlags, + void *pvUser) +{ + const struct ping_pcb *pcb = (const struct ping_pcb *)pvValue; + size_t cb = 0; + + NOREF(cchWidth); + NOREF(cchPrecision); + NOREF(fFlags); + NOREF(pvUser); + + AssertReturn(strcmp(pszType, "ping_pcb") == 0, 0); + + if (pcb == NULL) { + return RTStrFormat(pfnOutput, pvArgOutput, NULL, NULL, "(null)"); + } + + /* XXX: %RTnaipv4 takes the value, but %RTnaipv6 takes the pointer */ + if (pcb->is_ipv6) { + cb += RTStrFormat(pfnOutput, pvArgOutput, NULL, NULL, + "%RTnaipv6 -> %RTnaipv6", &pcb->src, &pcb->dst); + if (pcb->is_mapped) { + cb += RTStrFormat(pfnOutput, pvArgOutput, NULL, NULL, + " (%RTnaipv6)", &pcb->peer.sin6.sin6_addr); + } + } + else { + cb += RTStrFormat(pfnOutput, pvArgOutput, NULL, NULL, + "%RTnaipv4 -> %RTnaipv4", + ip4_addr_get_u32(ipX_2_ip(&pcb->src)), + ip4_addr_get_u32(ipX_2_ip(&pcb->dst))); + if (pcb->is_mapped) { + cb += RTStrFormat(pfnOutput, pvArgOutput, NULL, NULL, + " (%RTnaipv4)", pcb->peer.sin.sin_addr.s_addr); + } + } + + cb += RTStrFormat(pfnOutput, pvArgOutput, NULL, NULL, + " id %04x->%04x", ntohs(pcb->guest_id), ntohs(pcb->host_id)); + + return cb; +} + + +static struct ping_pcb * +pxping_pcb_allocate(struct pxping *pxping) +{ + struct ping_pcb *pcb; + + if (pxping->npcbs >= PXPING_MAX_PCBS) { + return NULL; + } + + pcb = (struct ping_pcb *)malloc(sizeof(*pcb)); + if (pcb == NULL) { + return NULL; + } + + ++pxping->npcbs; + return pcb; +} + + +static void +pxping_pcb_delete(struct pxping *pxping, struct ping_pcb *pcb) +{ + LWIP_ASSERT1(pxping->npcbs > 0); + LWIP_ASSERT1(pcb->next == NULL); + LWIP_ASSERT1(pcb->pprev_timeout == NULL); + + DPRINTF(("%s: ping %p\n", __func__, (void *)pcb)); + + --pxping->npcbs; + free(pcb); +} + + +static void +pxping_timeout_add(struct pxping *pxping, struct ping_pcb *pcb) +{ + struct ping_pcb **chain; + + LWIP_ASSERT1(pcb->pprev_timeout == NULL); + + chain = &pxping->timeout_list[pcb->timeout_slot]; + if ((pcb->next_timeout = *chain) != NULL) { + (*chain)->pprev_timeout = &pcb->next_timeout; + } + *chain = pcb; + pcb->pprev_timeout = chain; +} + + +static void +pxping_timeout_del(struct pxping *pxping, struct ping_pcb *pcb) +{ + LWIP_UNUSED_ARG(pxping); + + LWIP_ASSERT1(pcb->pprev_timeout != NULL); + if (pcb->next_timeout != NULL) { + pcb->next_timeout->pprev_timeout = pcb->pprev_timeout; + } + *pcb->pprev_timeout = pcb->next_timeout; + pcb->pprev_timeout = NULL; + pcb->next_timeout = NULL; +} + + +static void +pxping_pcb_register(struct pxping *pxping, struct ping_pcb *pcb) +{ + pcb->next = pxping->pcbs; + pxping->pcbs = pcb; + + pxping_timeout_add(pxping, pcb); +} + + +static void +pxping_pcb_deregister(struct pxping *pxping, struct ping_pcb *pcb) +{ + struct ping_pcb **p; + + for (p = &pxping->pcbs; *p != NULL; p = &(*p)->next) { + if (*p == pcb) { + *p = pcb->next; + pcb->next = NULL; + break; + } + } + + pxping_timeout_del(pxping, pcb); +} + + +static struct ping_pcb * +pxping_pcb_for_request(struct pxping *pxping, + int is_ipv6, ipX_addr_t *src, ipX_addr_t *dst, + u16_t guest_id) +{ + struct ping_pcb *pcb; + + /* on lwip thread, so no concurrent updates */ + for (pcb = pxping->pcbs; pcb != NULL; pcb = pcb->next) { + if (pcb->guest_id == guest_id + && pcb->is_ipv6 == is_ipv6 + && ipX_addr_cmp(is_ipv6, &pcb->dst, dst) + && ipX_addr_cmp(is_ipv6, &pcb->src, src)) + { + break; + } + } + + if (pcb == NULL) { + int mapped; + + pcb = pxping_pcb_allocate(pxping); + if (pcb == NULL) { + return NULL; + } + + pcb->is_ipv6 = is_ipv6; + ipX_addr_copy(is_ipv6, pcb->src, *src); + ipX_addr_copy(is_ipv6, pcb->dst, *dst); + + pcb->guest_id = guest_id; +#ifdef RT_OS_WINDOWS +# define random() (rand()) +#endif + pcb->host_id = random() & 0xffffUL; + + pcb->pprev_timeout = NULL; + pcb->next_timeout = NULL; + + if (is_ipv6) { + pcb->peer.sin6.sin6_family = AF_INET6; +#if HAVE_SA_LEN + pcb->peer.sin6.sin6_len = sizeof(pcb->peer.sin6); +#endif + pcb->peer.sin6.sin6_port = htons(IPPROTO_ICMPV6); + pcb->peer.sin6.sin6_flowinfo = 0; + mapped = pxremap_outbound_ip6((ip6_addr_t *)&pcb->peer.sin6.sin6_addr, + ipX_2_ip6(&pcb->dst)); + } + else { + pcb->peer.sin.sin_family = AF_INET; +#if HAVE_SA_LEN + pcb->peer.sin.sin_len = sizeof(pcb->peer.sin); +#endif + pcb->peer.sin.sin_port = htons(IPPROTO_ICMP); + mapped = pxremap_outbound_ip4((ip_addr_t *)&pcb->peer.sin.sin_addr, + ipX_2_ip(&pcb->dst)); + } + + if (mapped == PXREMAP_FAILED) { + free(pcb); + return NULL; + } + else { + pcb->is_mapped = (mapped == PXREMAP_MAPPED); + } + + pcb->timeout_slot = pxping->timeout_slot; + + sys_mutex_lock(&pxping->lock); + pxping_pcb_register(pxping, pcb); + sys_mutex_unlock(&pxping->lock); + + DPRINTF(("ping %p: %R[ping_pcb] - created\n", pcb, pcb)); + + pxping_timer_needed(pxping); + } + else { + /* just bump up expiration timeout lazily */ + DPRINTF(("ping %p: %R[ping_pcb] - slot %d -> %d\n", + pcb, pcb, + (unsigned int)pcb->timeout_slot, + (unsigned int)pxping->timeout_slot)); + pcb->timeout_slot = pxping->timeout_slot; + } + + return pcb; +} + + +/* GCC 12.2.1 complains that array subscript is partly outside + * of array bounds in expansion of ipX_addr_cmp. */ +#if RT_GNUC_PREREQ(12, 0) +# pragma GCC diagnostic push +# pragma GCC diagnostic ignored "-Warray-bounds" +#endif +/** + * Called on pollmgr thread. Caller must do the locking since caller + * is going to use the returned pcb, which needs to be protected from + * being expired by pxping_timer() on lwip thread. + */ +static struct ping_pcb * +pxping_pcb_for_reply(struct pxping *pxping, + int is_ipv6, ipX_addr_t *dst, u16_t host_id) +{ + struct ping_pcb *pcb; + + for (pcb = pxping->pcbs; pcb != NULL; pcb = pcb->next) { + if (pcb->host_id == host_id + && pcb->is_ipv6 == is_ipv6 + /* XXX: allow broadcast pings? */ + && ipX_addr_cmp(is_ipv6, &pcb->dst, dst)) + { + return pcb; + } + } + + return NULL; +} +#if RT_GNUC_PREREQ(12, 0) +# pragma GCC diagnostic pop +#endif + + +static void +pxping_timer(void *arg) +{ + struct pxping *pxping = (struct pxping *)arg; + struct ping_pcb **chain, *pcb; + + pxping->timer_active = 0; + + /* + * New slot points to the list of pcbs to check for expiration. + */ + LWIP_ASSERT1(pxping->timeout_slot < TIMEOUT); + if (++pxping->timeout_slot == TIMEOUT) { + pxping->timeout_slot = 0; + } + + chain = &pxping->timeout_list[pxping->timeout_slot]; + pcb = *chain; + + /* protect from pollmgr concurrent reads */ + sys_mutex_lock(&pxping->lock); + + while (pcb != NULL) { + struct ping_pcb *xpcb = pcb; + pcb = pcb->next_timeout; + + if (xpcb->timeout_slot == pxping->timeout_slot) { + /* expired */ + pxping_pcb_deregister(pxping, xpcb); + pxping_pcb_delete(pxping, xpcb); + } + else { + /* + * If there was another request, we updated timeout_slot + * but delayed actually moving the pcb until now. + */ + pxping_timeout_del(pxping, xpcb); /* from current slot */ + pxping_timeout_add(pxping, xpcb); /* to new slot */ + } + } + + sys_mutex_unlock(&pxping->lock); + pxping_timer_needed(pxping); +} + + +static void +pxping_timer_needed(struct pxping *pxping) +{ + if (!pxping->timer_active && pxping->pcbs != NULL) { + pxping->timer_active = 1; + sys_timeout(1 * 1000, pxping_timer, pxping); + } +} + + +static int +pxping_pmgr_pump(struct pollmgr_handler *handler, SOCKET fd, int revents) +{ + struct pxping *pxping; + + pxping = (struct pxping *)handler->data; + LWIP_ASSERT1(fd == pxping->sock4 || fd == pxping->sock6); + + if (revents & ~(POLLIN|POLLERR)) { + DPRINTF0(("%s: unexpected revents 0x%x\n", __func__, revents)); + return POLLIN; + } + + if (revents & POLLERR) { + int sockerr = -1; + socklen_t optlen = (socklen_t)sizeof(sockerr); + int status; + + status = getsockopt(fd, SOL_SOCKET, + SO_ERROR, (char *)&sockerr, &optlen); + if (status < 0) { + DPRINTF(("%s: sock %d: SO_ERROR failed: %R[sockerr]\n", + __func__, fd, SOCKERRNO())); + } + else { + DPRINTF(("%s: sock %d: %R[sockerr]\n", + __func__, fd, sockerr)); + } + } + + if ((revents & POLLIN) == 0) { + return POLLIN; + } + + if (fd == pxping->sock4) { + pxping_pmgr_icmp4(pxping); + } + else /* fd == pxping->sock6 */ { + pxping_pmgr_icmp6(pxping); + } + + return POLLIN; +} + + +/** + * Process incoming ICMP message for the host. + * NB: we will get a lot of spam here and have to sift through it. + */ +static void +pxping_pmgr_icmp4(struct pxping *pxping) +{ + struct sockaddr_in sin; + socklen_t salen = sizeof(sin); + ssize_t nread; + struct ip_hdr *iph; + struct icmp_echo_hdr *icmph; + u16_t iplen, ipoff; + + memset(&sin, 0, sizeof(sin)); + + /* + * Reads from raw IPv4 sockets deliver complete IP datagrams with + * IP header included. + */ + nread = recvfrom(pxping->sock4, pollmgr_udpbuf, sizeof(pollmgr_udpbuf), 0, + (struct sockaddr *)&sin, &salen); + if (nread < 0) { + DPRINTF(("%s: %R[sockerr]\n", __func__, SOCKERRNO())); + return; + } + + if (nread < IP_HLEN) { + DPRINTF2(("%s: read %d bytes, IP header truncated\n", + __func__, (unsigned int)nread)); + return; + } + + iph = (struct ip_hdr *)pollmgr_udpbuf; + + /* match version */ + if (IPH_V(iph) != 4) { + DPRINTF2(("%s: unexpected IP version %d\n", __func__, IPH_V(iph))); + return; + } + + /* no fragmentation */ + ipoff = IPH_OFFSET(iph); +#if defined(RT_OS_DARWIN) + /* darwin reports IPH_OFFSET in host byte order */ + ipoff = htons(ipoff); + IPH_OFFSET_SET(iph, ipoff); +#endif + if ((ipoff & PP_HTONS(IP_OFFMASK | IP_MF)) != 0) { + DPRINTF2(("%s: dropping fragmented datagram (0x%04x)\n", + __func__, ntohs(ipoff))); + return; + } + + /* no options */ + if (IPH_HL(iph) * 4 != IP_HLEN) { + DPRINTF2(("%s: dropping datagram with options (IP header length %d)\n", + __func__, IPH_HL(iph) * 4)); + return; + } + + if (IPH_PROTO(iph) != IP_PROTO_ICMP) { + DPRINTF2(("%s: unexpected protocol %d\n", __func__, IPH_PROTO(iph))); + return; + } + + iplen = IPH_LEN(iph); +#if !defined(RT_OS_DARWIN) + /* darwin reports IPH_LEN in host byte order */ + iplen = ntohs(iplen); +#endif +#if defined(RT_OS_DARWIN) || defined(RT_OS_SOLARIS) + /* darwin and solaris change IPH_LEN to payload length only */ + iplen += IP_HLEN; /* we verified there are no options */ + IPH_LEN_SET(iph, htons(iplen)); +#endif + if (nread < iplen) { + DPRINTF2(("%s: read %d bytes but total length is %d bytes\n", + __func__, (unsigned int)nread, (unsigned int)iplen)); + return; + } + + if (iplen < IP_HLEN + ICMP_HLEN) { + DPRINTF2(("%s: IP length %d bytes, ICMP header truncated\n", + __func__, iplen)); + return; + } + + icmph = (struct icmp_echo_hdr *)(pollmgr_udpbuf + IP_HLEN); + if (ICMPH_TYPE(icmph) == ICMP_ER) { + pxping_pmgr_icmp4_echo(pxping, iplen, &sin); + } + else if (ICMPH_TYPE(icmph) == ICMP_DUR || ICMPH_TYPE(icmph) == ICMP_TE) { + pxping_pmgr_icmp4_error(pxping, iplen, &sin); + } +#if 1 + else { + DPRINTF2(("%s: ignoring ICMP type %d\n", __func__, ICMPH_TYPE(icmph))); + } +#endif +} + + +/** + * Check if this incoming ICMP echo reply is for one of our pings and + * forward it to the guest. + */ +static void +pxping_pmgr_icmp4_echo(struct pxping *pxping, + u16_t iplen, struct sockaddr_in *peer) +{ + struct ip_hdr *iph; + struct icmp_echo_hdr *icmph; + u16_t id, seq; + ip_addr_t guest_ip, target_ip; + int mapped; + struct ping_pcb *pcb; + u16_t guest_id; + u16_t oipsum; + u32_t sum; + RT_NOREF(peer); + + iph = (struct ip_hdr *)pollmgr_udpbuf; + icmph = (struct icmp_echo_hdr *)(pollmgr_udpbuf + IP_HLEN); + + id = icmph->id; + seq = icmph->seqno; + + DPRINTF(("<--- PING %RTnaipv4 id 0x%x seq %d\n", + peer->sin_addr.s_addr, ntohs(id), ntohs(seq))); + + /* + * Is this a reply to one of our pings? + */ + + ip_addr_copy(target_ip, iph->src); + mapped = pxremap_inbound_ip4(&target_ip, &target_ip); + if (mapped == PXREMAP_FAILED) { + return; + } + if (mapped == PXREMAP_ASIS && IPH_TTL(iph) == 1) { + DPRINTF2(("%s: dropping packet with ttl 1\n", __func__)); + return; + } + + sys_mutex_lock(&pxping->lock); + pcb = pxping_pcb_for_reply(pxping, 0, ip_2_ipX(&target_ip), id); + if (pcb == NULL) { + sys_mutex_unlock(&pxping->lock); + DPRINTF2(("%s: no match\n", __func__)); + return; + } + + DPRINTF2(("%s: pcb %p\n", __func__, (void *)pcb)); + + /* save info before unlocking since pcb may expire */ + ip_addr_copy(guest_ip, *ipX_2_ip(&pcb->src)); + guest_id = pcb->guest_id; + + sys_mutex_unlock(&pxping->lock); + + + /* + * Rewrite headers and forward to guest. + */ + + /* rewrite ICMP echo header */ + sum = (u16_t)~icmph->chksum; + sum += chksum_update_16(&icmph->id, guest_id); + sum = FOLD_U32T(sum); + icmph->chksum = ~sum; + + /* rewrite IP header */ + oipsum = IPH_CHKSUM(iph); + if (oipsum == 0) { + /* Solaris doesn't compute checksum for local replies */ + ip_addr_copy(iph->dest, guest_ip); + if (mapped == PXREMAP_MAPPED) { + ip_addr_copy(iph->src, target_ip); + } + else { + IPH_TTL_SET(iph, IPH_TTL(iph) - 1); + } + IPH_CHKSUM_SET(iph, inet_chksum(iph, ntohs(IPH_LEN(iph)))); + } + else { + sum = (u16_t)~oipsum; + sum += chksum_update_32((u32_t *)&iph->dest, + ip4_addr_get_u32(&guest_ip)); + if (mapped == PXREMAP_MAPPED) { + sum += chksum_update_32((u32_t *)&iph->src, + ip4_addr_get_u32(&target_ip)); + } + else { + IPH_TTL_SET(iph, IPH_TTL(iph) - 1); + sum += PP_NTOHS(~0x0100); + } + sum = FOLD_U32T(sum); + IPH_CHKSUM_SET(iph, ~sum); + } + + pxping_pmgr_forward_inbound(pxping, iplen); +} + + +/** + * Check if this incoming ICMP error (destination unreachable or time + * exceeded) is about one of our pings and forward it to the guest. + */ +static void +pxping_pmgr_icmp4_error(struct pxping *pxping, + u16_t iplen, struct sockaddr_in *peer) +{ + struct ip_hdr *iph, *oiph; + struct icmp_echo_hdr *icmph, *oicmph; + u16_t oipoff, oiphlen, oiplen; + u16_t id, seq; + ip_addr_t guest_ip, target_ip, error_ip; + int target_mapped, error_mapped; + struct ping_pcb *pcb; + u16_t guest_id; + u32_t sum; + RT_NOREF(peer); + + iph = (struct ip_hdr *)pollmgr_udpbuf; + icmph = (struct icmp_echo_hdr *)(pollmgr_udpbuf + IP_HLEN); + + /* + * Inner IP datagram is not checked by the kernel and may be + * anything, possibly malicious. + */ + + oipoff = IP_HLEN + ICMP_HLEN; + oiplen = iplen - oipoff; /* NB: truncated length, not IPH_LEN(oiph) */ + if (oiplen < IP_HLEN) { + DPRINTF2(("%s: original datagram truncated to %d bytes\n", + __func__, oiplen)); + } + + /* IP header of the original message */ + oiph = (struct ip_hdr *)(pollmgr_udpbuf + oipoff); + + /* match version */ + if (IPH_V(oiph) != 4) { + DPRINTF2(("%s: unexpected IP version %d\n", __func__, IPH_V(oiph))); + return; + } + + /* can't match fragments except the first one */ + if ((IPH_OFFSET(oiph) & PP_HTONS(IP_OFFMASK)) != 0) { + DPRINTF2(("%s: ignoring fragment with offset %d\n", + __func__, ntohs(IPH_OFFSET(oiph) & PP_HTONS(IP_OFFMASK)))); + return; + } + + if (IPH_PROTO(oiph) != IP_PROTO_ICMP) { +#if 0 + /* don't spam with every "destination unreachable" in the system */ + DPRINTF2(("%s: ignoring protocol %d\n", __func__, IPH_PROTO(oiph))); +#endif + return; + } + + oiphlen = IPH_HL(oiph) * 4; + if (oiplen < oiphlen + ICMP_HLEN) { + DPRINTF2(("%s: original datagram truncated to %d bytes\n", + __func__, oiplen)); + return; + } + + oicmph = (struct icmp_echo_hdr *)(pollmgr_udpbuf + oipoff + oiphlen); + if (ICMPH_TYPE(oicmph) != ICMP_ECHO) { + DPRINTF2(("%s: ignoring ICMP error for original ICMP type %d\n", + __func__, ICMPH_TYPE(oicmph))); + return; + } + + id = oicmph->id; + seq = oicmph->seqno; + + DPRINTF2(("%s: ping %RTnaipv4 id 0x%x seq %d", + __func__, ip4_addr_get_u32(&oiph->dest), ntohs(id), ntohs(seq))); + if (ICMPH_TYPE(icmph) == ICMP_DUR) { + DPRINTF2((" unreachable (code %d)\n", ICMPH_CODE(icmph))); + } + else { + DPRINTF2((" time exceeded\n")); + } + + + /* + * Is the inner (failed) datagram one of our pings? + */ + + ip_addr_copy(target_ip, oiph->dest); /* inner (failed) */ + target_mapped = pxremap_inbound_ip4(&target_ip, &target_ip); + if (target_mapped == PXREMAP_FAILED) { + return; + } + + sys_mutex_lock(&pxping->lock); + pcb = pxping_pcb_for_reply(pxping, 0, ip_2_ipX(&target_ip), id); + if (pcb == NULL) { + sys_mutex_unlock(&pxping->lock); + DPRINTF2(("%s: no match\n", __func__)); + return; + } + + DPRINTF2(("%s: pcb %p\n", __func__, (void *)pcb)); + + /* save info before unlocking since pcb may expire */ + ip_addr_copy(guest_ip, *ipX_2_ip(&pcb->src)); + guest_id = pcb->guest_id; + + sys_mutex_unlock(&pxping->lock); + + + /* + * Rewrite both inner and outer headers and forward to guest. + * Note that the checksum of the outer ICMP error message is + * preserved by the changes we do to inner headers. + */ + + ip_addr_copy(error_ip, iph->src); /* node that reports the error */ + error_mapped = pxremap_inbound_ip4(&error_ip, &error_ip); + if (error_mapped == PXREMAP_FAILED) { + return; + } + if (error_mapped == PXREMAP_ASIS && IPH_TTL(iph) == 1) { + DPRINTF2(("%s: dropping packet with ttl 1\n", __func__)); + return; + } + + /* rewrite inner ICMP echo header */ + sum = (u16_t)~oicmph->chksum; + sum += chksum_update_16(&oicmph->id, guest_id); + sum = FOLD_U32T(sum); + oicmph->chksum = ~sum; + + /* rewrite inner IP header */ +#if defined(RT_OS_DARWIN) + /* darwin converts inner length to host byte order too */ + IPH_LEN_SET(oiph, htons(IPH_LEN(oiph))); +#endif + sum = (u16_t)~IPH_CHKSUM(oiph); + sum += chksum_update_32((u32_t *)&oiph->src, ip4_addr_get_u32(&guest_ip)); + if (target_mapped == PXREMAP_MAPPED) { + sum += chksum_update_32((u32_t *)&oiph->dest, ip4_addr_get_u32(&target_ip)); + } + sum = FOLD_U32T(sum); + IPH_CHKSUM_SET(oiph, ~sum); + + /* rewrite outer IP header */ + sum = (u16_t)~IPH_CHKSUM(iph); + sum += chksum_update_32((u32_t *)&iph->dest, ip4_addr_get_u32(&guest_ip)); + if (error_mapped == PXREMAP_MAPPED) { + sum += chksum_update_32((u32_t *)&iph->src, ip4_addr_get_u32(&error_ip)); + } + else { + IPH_TTL_SET(iph, IPH_TTL(iph) - 1); + sum += PP_NTOHS(~0x0100); + } + sum = FOLD_U32T(sum); + IPH_CHKSUM_SET(iph, ~sum); + + pxping_pmgr_forward_inbound(pxping, iplen); +} + + +/** + * Process incoming ICMPv6 message for the host. + * NB: we will get a lot of spam here and have to sift through it. + */ +static void +pxping_pmgr_icmp6(struct pxping *pxping) +{ +#ifndef RT_OS_WINDOWS + struct msghdr mh; + ssize_t nread; +#else + WSAMSG mh; + DWORD nread; +#endif + IOVEC iov[1]; + static u8_t cmsgbuf[128]; + struct cmsghdr *cmh; + struct sockaddr_in6 sin6; + /* socklen_t salen = sizeof(sin6); - unused */ + struct icmp6_echo_hdr *icmph; + struct in6_pktinfo *pktinfo; + int hopl, tclass; +#ifdef RT_OS_WINDOWS + int status; +#endif + + /* + * Reads from raw IPv6 sockets deliver only the payload. Full + * headers are available via recvmsg(2)/cmsg(3). + */ + IOVEC_SET_BASE(iov[0], pollmgr_udpbuf); + IOVEC_SET_LEN(iov[0], sizeof(pollmgr_udpbuf)); + + memset(&mh, 0, sizeof(mh)); +#ifndef RT_OS_WINDOWS + mh.msg_name = &sin6; + mh.msg_namelen = sizeof(sin6); + mh.msg_iov = iov; + mh.msg_iovlen = 1; + mh.msg_control = cmsgbuf; + mh.msg_controllen = sizeof(cmsgbuf); + mh.msg_flags = 0; + + nread = recvmsg(pxping->sock6, &mh, 0); + if (nread < 0) { + DPRINTF(("%s: %R[sockerr]\n", __func__, SOCKERRNO())); + return; + } +#else /* RT_OS_WINDOWS */ + mh.name = (LPSOCKADDR)&sin6; + mh.namelen = sizeof(sin6); + mh.lpBuffers = iov; + mh.dwBufferCount = 1; + mh.Control.buf = cmsgbuf; + mh.Control.len = sizeof(cmsgbuf); + mh.dwFlags = 0; + + status = (*pxping->pfWSARecvMsg6)(pxping->sock6, &mh, &nread, NULL, NULL); + if (status == SOCKET_ERROR) { + DPRINTF2(("%s: error %d\n", __func__, WSAGetLastError())); + return; + } +#endif + + icmph = (struct icmp6_echo_hdr *)pollmgr_udpbuf; + + DPRINTF2(("%s: %RTnaipv6 ICMPv6: ", __func__, &sin6.sin6_addr)); + + if (icmph->type == ICMP6_TYPE_EREP) { + DPRINTF2(("echo reply %04x %u\n", + (unsigned int)icmph->id, (unsigned int)icmph->seqno)); + } + else { /* XXX */ + if (icmph->type == ICMP6_TYPE_EREQ) { + DPRINTF2(("echo request %04x %u\n", + (unsigned int)icmph->id, (unsigned int)icmph->seqno)); + } + else if (icmph->type == ICMP6_TYPE_DUR) { + DPRINTF2(("destination unreachable\n")); + } + else if (icmph->type == ICMP6_TYPE_PTB) { + DPRINTF2(("packet too big\n")); + } + else if (icmph->type == ICMP6_TYPE_TE) { + DPRINTF2(("time exceeded\n")); + } + else if (icmph->type == ICMP6_TYPE_PP) { + DPRINTF2(("parameter problem\n")); + } + else { + DPRINTF2(("type %d len %u\n", icmph->type, (unsigned int)nread)); + } + + if (icmph->type >= ICMP6_TYPE_EREQ) { + return; /* informational message */ + } + } + + pktinfo = NULL; + hopl = -1; + tclass = -1; + for (cmh = CMSG_FIRSTHDR(&mh); cmh != NULL; cmh = CMSG_NXTHDR(&mh, cmh)) { + if (cmh->cmsg_len == 0) + break; + + if (cmh->cmsg_level == IPPROTO_IPV6 + && cmh->cmsg_type == IPV6_HOPLIMIT + && cmh->cmsg_len == CMSG_LEN(sizeof(int))) + { + hopl = *(int *)CMSG_DATA(cmh); + DPRINTF2(("hoplimit = %d\n", hopl)); + } + + if (cmh->cmsg_level == IPPROTO_IPV6 + && cmh->cmsg_type == IPV6_PKTINFO + && cmh->cmsg_len == CMSG_LEN(sizeof(struct in6_pktinfo))) + { + pktinfo = (struct in6_pktinfo *)CMSG_DATA(cmh); + DPRINTF2(("pktinfo found\n")); + } + } + + if (pktinfo == NULL) { + /* + * ip6_output_if() doesn't do checksum for us so we need to + * manually recompute it - for this we must know the + * destination address of the pseudo-header that we will + * rewrite with guest's address. (TODO: yeah, yeah, we can + * compute it from scratch...) + */ + DPRINTF2(("%s: unable to get pktinfo\n", __func__)); + return; + } + + if (hopl < 0) { + hopl = LWIP_ICMP6_HL; + } + + if (icmph->type == ICMP6_TYPE_EREP) { + pxping_pmgr_icmp6_echo(pxping, + (ip6_addr_t *)&sin6.sin6_addr, + (ip6_addr_t *)&pktinfo->ipi6_addr, + hopl, tclass, (u16_t)nread); + } + else if (icmph->type < ICMP6_TYPE_EREQ) { + pxping_pmgr_icmp6_error(pxping, + (ip6_addr_t *)&sin6.sin6_addr, + (ip6_addr_t *)&pktinfo->ipi6_addr, + hopl, tclass, (u16_t)nread); + } +} + + +/** + * Check if this incoming ICMPv6 echo reply is for one of our pings + * and forward it to the guest. + */ +static void +pxping_pmgr_icmp6_echo(struct pxping *pxping, + ip6_addr_t *src, ip6_addr_t *dst, + int hopl, int tclass, u16_t icmplen) +{ + struct icmp6_echo_hdr *icmph; + ip6_addr_t guest_ip, target_ip; + int mapped; + struct ping_pcb *pcb; + u16_t id, guest_id; + u32_t sum; + + ip6_addr_copy(target_ip, *src); + mapped = pxremap_inbound_ip6(&target_ip, &target_ip); + if (mapped == PXREMAP_FAILED) { + return; + } + else if (mapped == PXREMAP_ASIS) { + if (hopl == 1) { + DPRINTF2(("%s: dropping packet with ttl 1\n", __func__)); + return; + } + --hopl; + } + + icmph = (struct icmp6_echo_hdr *)pollmgr_udpbuf; + id = icmph->id; + + sys_mutex_lock(&pxping->lock); + pcb = pxping_pcb_for_reply(pxping, 1, ip6_2_ipX(&target_ip), id); + if (pcb == NULL) { + sys_mutex_unlock(&pxping->lock); + DPRINTF2(("%s: no match\n", __func__)); + return; + } + + DPRINTF2(("%s: pcb %p\n", __func__, (void *)pcb)); + + /* save info before unlocking since pcb may expire */ + ip6_addr_copy(guest_ip, *ipX_2_ip6(&pcb->src)); + guest_id = pcb->guest_id; + + sys_mutex_unlock(&pxping->lock); + + /* rewrite ICMPv6 echo header */ + sum = (u16_t)~icmph->chksum; + sum += chksum_update_16(&icmph->id, guest_id); + sum += chksum_delta_ipv6(dst, &guest_ip); /* pseudo */ + if (mapped) { + sum += chksum_delta_ipv6(src, &target_ip); /* pseudo */ + } + sum = FOLD_U32T(sum); + icmph->chksum = ~sum; + + pxping_pmgr_forward_inbound6(pxping, + &target_ip, /* echo reply src */ + &guest_ip, /* echo reply dst */ + hopl, tclass, icmplen); +} + + +/** + * Check if this incoming ICMPv6 error is about one of our pings and + * forward it to the guest. + */ +static void +pxping_pmgr_icmp6_error(struct pxping *pxping, + ip6_addr_t *src, ip6_addr_t *dst, + int hopl, int tclass, u16_t icmplen) +{ + struct icmp6_hdr *icmph; + u8_t *bufptr; + size_t buflen, hlen; + int proto; + struct ip6_hdr *oiph; + struct icmp6_echo_hdr *oicmph; + struct ping_pcb *pcb; + ip6_addr_t guest_ip, target_ip, error_ip; + int target_mapped, error_mapped; + u16_t guest_id; + u32_t sum; + + icmph = (struct icmp6_hdr *)pollmgr_udpbuf; + + /* + * Inner IP datagram is not checked by the kernel and may be + * anything, possibly malicious. + */ + oiph = NULL; + oicmph = NULL; + + bufptr = pollmgr_udpbuf; + buflen = icmplen; + + hlen = sizeof(*icmph); + proto = IP6_NEXTH_ENCAPS; /* i.e. IPv6, lwIP's name is unfortuate */ + for (;;) { + if (hlen > buflen) { + DPRINTF2(("truncated datagram inside ICMPv6 error message is too short\n")); + return; + } + buflen -= hlen; + bufptr += hlen; + + if (proto == IP6_NEXTH_ENCAPS && oiph == NULL) { /* outermost IPv6 */ + oiph = (struct ip6_hdr *)bufptr; + if (IP6H_V(oiph) != 6) { + DPRINTF2(("%s: unexpected IP version %d\n", __func__, IP6H_V(oiph))); + return; + } + + proto = IP6H_NEXTH(oiph); + hlen = IP6_HLEN; + } + else if (proto == IP6_NEXTH_ICMP6) { + oicmph = (struct icmp6_echo_hdr *)bufptr; + break; + } + else if (proto == IP6_NEXTH_ROUTING + || proto == IP6_NEXTH_HOPBYHOP + || proto == IP6_NEXTH_DESTOPTS) + { + proto = bufptr[0]; + hlen = (bufptr[1] + 1) * 8; + } + else { + DPRINTF2(("%s: stopping at protocol %d\n", __func__, proto)); + break; + } + } + + if (oiph == NULL || oicmph == NULL) { + return; + } + + if (buflen < sizeof(*oicmph)) { + DPRINTF2(("%s: original ICMPv6 is truncated too short\n", __func__)); + return; + } + + if (oicmph->type != ICMP6_TYPE_EREQ) { + DPRINTF2(("%s: ignoring original ICMPv6 type %d\n", __func__, oicmph->type)); + return; + } + + ip6_addr_copy(target_ip, oiph->dest); /* inner (failed) */ + target_mapped = pxremap_inbound_ip6(&target_ip, &target_ip); + if (target_mapped == PXREMAP_FAILED) { + return; + } + + sys_mutex_lock(&pxping->lock); + pcb = pxping_pcb_for_reply(pxping, 1, ip6_2_ipX(&target_ip), oicmph->id); + if (pcb == NULL) { + sys_mutex_unlock(&pxping->lock); + DPRINTF2(("%s: no match\n", __func__)); + return; + } + + DPRINTF2(("%s: pcb %p\n", __func__, (void *)pcb)); + + /* save info before unlocking since pcb may expire */ + ip6_addr_copy(guest_ip, *ipX_2_ip6(&pcb->src)); + guest_id = pcb->guest_id; + + sys_mutex_unlock(&pxping->lock); + + + /* + * Rewrite inner and outer headers and forward to guest. Note + * that IPv6 has no IP header checksum, but uses pseudo-header for + * ICMPv6, so we update both in one go, adjusting ICMPv6 checksum + * as we rewrite IP header. + */ + + ip6_addr_copy(error_ip, *src); /* node that reports the error */ + error_mapped = pxremap_inbound_ip6(&error_ip, &error_ip); + if (error_mapped == PXREMAP_FAILED) { + return; + } + if (error_mapped == PXREMAP_ASIS && hopl == 1) { + DPRINTF2(("%s: dropping packet with ttl 1\n", __func__)); + return; + } + + /* rewrite inner ICMPv6 echo header and inner IPv6 header */ + sum = (u16_t)~oicmph->chksum; + sum += chksum_update_16(&oicmph->id, guest_id); + sum += chksum_update_ipv6((ip6_addr_t *)&oiph->src, &guest_ip); + if (target_mapped) { + sum += chksum_delta_ipv6((ip6_addr_t *)&oiph->dest, &target_ip); + } + sum = FOLD_U32T(sum); + oicmph->chksum = ~sum; + + /* rewrite outer ICMPv6 error header */ + sum = (u16_t)~icmph->chksum; + sum += chksum_delta_ipv6(dst, &guest_ip); /* pseudo */ + if (error_mapped) { + sum += chksum_delta_ipv6(src, &error_ip); /* pseudo */ + } + sum = FOLD_U32T(sum); + icmph->chksum = ~sum; + + pxping_pmgr_forward_inbound6(pxping, + &error_ip, /* error src */ + &guest_ip, /* error dst */ + hopl, tclass, icmplen); +} + + +/** + * Hand off ICMP datagram to the lwip thread where it will be + * forwarded to the guest. + * + * We no longer need ping_pcb. The pcb may get expired on the lwip + * thread, but we have already patched necessary information into the + * datagram. + */ +static void +pxping_pmgr_forward_inbound(struct pxping *pxping, u16_t iplen) +{ + struct pbuf *p; + struct ping_msg *msg; + err_t error; + + p = pbuf_alloc(PBUF_LINK, iplen, PBUF_RAM); + if (p == NULL) { + DPRINTF(("%s: pbuf_alloc(%d) failed\n", + __func__, (unsigned int)iplen)); + return; + } + + error = pbuf_take(p, pollmgr_udpbuf, iplen); + if (error != ERR_OK) { + DPRINTF(("%s: pbuf_take(%d) failed\n", + __func__, (unsigned int)iplen)); + pbuf_free(p); + return; + } + + msg = (struct ping_msg *)malloc(sizeof(*msg)); + if (msg == NULL) { + pbuf_free(p); + return; + } + + msg->msg.type = TCPIP_MSG_CALLBACK_STATIC; + msg->msg.sem = NULL; + msg->msg.msg.cb.function = pxping_pcb_forward_inbound; + msg->msg.msg.cb.ctx = (void *)msg; + + msg->pxping = pxping; + msg->p = p; + + proxy_lwip_post(&msg->msg); +} + + +static void +pxping_pcb_forward_inbound(void *arg) +{ + struct ping_msg *msg = (struct ping_msg *)arg; + err_t error; + + LWIP_ASSERT1(msg != NULL); + LWIP_ASSERT1(msg->pxping != NULL); + LWIP_ASSERT1(msg->p != NULL); + + error = ip_raw_output_if(msg->p, msg->pxping->netif); + if (error != ERR_OK) { + DPRINTF(("%s: ip_output_if: %s\n", + __func__, proxy_lwip_strerr(error))); + } + pbuf_free(msg->p); + free(msg); +} + + +static void +pxping_pmgr_forward_inbound6(struct pxping *pxping, + ip6_addr_t *src, ip6_addr_t *dst, + u8_t hopl, u8_t tclass, + u16_t icmplen) +{ + struct pbuf *p; + struct ping6_msg *msg; + + err_t error; + + p = pbuf_alloc(PBUF_IP, icmplen, PBUF_RAM); + if (p == NULL) { + DPRINTF(("%s: pbuf_alloc(%d) failed\n", + __func__, (unsigned int)icmplen)); + return; + } + + error = pbuf_take(p, pollmgr_udpbuf, icmplen); + if (error != ERR_OK) { + DPRINTF(("%s: pbuf_take(%d) failed\n", + __func__, (unsigned int)icmplen)); + pbuf_free(p); + return; + } + + msg = (struct ping6_msg *)malloc(sizeof(*msg)); + if (msg == NULL) { + pbuf_free(p); + return; + } + + msg->msg.type = TCPIP_MSG_CALLBACK_STATIC; + msg->msg.sem = NULL; + msg->msg.msg.cb.function = pxping_pcb_forward_inbound6; + msg->msg.msg.cb.ctx = (void *)msg; + + msg->pxping = pxping; + msg->p = p; + ip6_addr_copy(msg->src, *src); + ip6_addr_copy(msg->dst, *dst); + msg->hopl = hopl; + msg->tclass = tclass; + + proxy_lwip_post(&msg->msg); +} + + +static void +pxping_pcb_forward_inbound6(void *arg) +{ + struct ping6_msg *msg = (struct ping6_msg *)arg; + err_t error; + + LWIP_ASSERT1(msg != NULL); + LWIP_ASSERT1(msg->pxping != NULL); + LWIP_ASSERT1(msg->p != NULL); + + error = ip6_output_if(msg->p, + &msg->src, &msg->dst, msg->hopl, msg->tclass, + IP6_NEXTH_ICMP6, msg->pxping->netif); + if (error != ERR_OK) { + DPRINTF(("%s: ip6_output_if: %s\n", + __func__, proxy_lwip_strerr(error))); + } + pbuf_free(msg->p); + free(msg); +} |