#include "slirp.h" /* host address */ struct in_addr our_addr; /* host dns address */ struct in_addr dns_addr; /* host loopback address */ struct in_addr loopback_addr; /* address for slirp virtual addresses */ struct in_addr special_addr; /* virtual address alias for host */ struct in_addr alias_addr; static const uint8_t special_ethaddr[6] = { 0x52, 0x54, 0x00, 0x12, 0x35, 0x00 }; uint8_t client_ethaddr[6]; int do_slowtimo; int link_up; struct timeval tt; FILE *lfd; struct ex_list *exec_list; /* XXX: suppress those select globals */ fd_set *global_readfds, *global_writefds, *global_xfds; char slirp_hostname[33]; #ifdef _WIN32 static int get_dns_addr(struct in_addr *pdns_addr) { FIXED_INFO *FixedInfo=NULL; ULONG BufLen; DWORD ret; IP_ADDR_STRING *pIPAddr; struct in_addr tmp_addr; FixedInfo = (FIXED_INFO *)GlobalAlloc(GPTR, sizeof(FIXED_INFO)); BufLen = sizeof(FIXED_INFO); if (ERROR_BUFFER_OVERFLOW == GetNetworkParams(FixedInfo, &BufLen)) { if (FixedInfo) { GlobalFree(FixedInfo); FixedInfo = NULL; } FixedInfo = GlobalAlloc(GPTR, BufLen); } if ((ret = GetNetworkParams(FixedInfo, &BufLen)) != ERROR_SUCCESS) { printf("GetNetworkParams failed. ret = %08x\n", (u_int)ret ); if (FixedInfo) { GlobalFree(FixedInfo); FixedInfo = NULL; } return -1; } pIPAddr = &(FixedInfo->DnsServerList); inet_aton(pIPAddr->IpAddress.String, &tmp_addr); *pdns_addr = tmp_addr; #if 0 printf( "DNS Servers:\n" ); printf( "DNS Addr:%s\n", pIPAddr->IpAddress.String ); pIPAddr = FixedInfo -> DnsServerList.Next; while ( pIPAddr ) { printf( "DNS Addr:%s\n", pIPAddr ->IpAddress.String ); pIPAddr = pIPAddr ->Next; } #endif if (FixedInfo) { GlobalFree(FixedInfo); FixedInfo = NULL; } return 0; } #else static int get_dns_addr(struct in_addr *pdns_addr) { char buff[512]; char buff2[256]; FILE *f; int found = 0; struct in_addr tmp_addr; f = fopen("/etc/resolv.conf", "r"); if (!f) return -1; #ifdef DEBUG lprint("IP address of your DNS(s): "); #endif while (fgets(buff, 512, f) != NULL) { if (sscanf(buff, "nameserver%*[ \t]%256s", buff2) == 1) { if (!inet_aton(buff2, &tmp_addr)) continue; if (tmp_addr.s_addr == loopback_addr.s_addr) tmp_addr = our_addr; /* If it's the first one, set it to dns_addr */ if (!found) *pdns_addr = tmp_addr; #ifdef DEBUG else lprint(", "); #endif if (++found > 3) { #ifdef DEBUG lprint("(more)"); #endif break; } #ifdef DEBUG else lprint("%s", inet_ntoa(tmp_addr)); #endif } } fclose(f); if (!found) return -1; return 0; } #endif #ifdef _WIN32 static void slirp_cleanup(void) { WSACleanup(); } #endif void slirp_init(void) { // debug_init("/tmp/slirp.log", DEBUG_DEFAULT); #ifdef _WIN32 { WSADATA Data; WSAStartup(MAKEWORD(2,0), &Data); atexit(slirp_cleanup); } #endif link_up = 1; if_init(); ip_init(); /* Initialise mbufs *after* setting the MTU */ m_init(); /* set default addresses */ inet_aton("127.0.0.1", &loopback_addr); if (get_dns_addr(&dns_addr) < 0) { dns_addr = loopback_addr; fprintf (stderr, "Warning: No DNS servers found\n"); } inet_aton(CTL_SPECIAL, &special_addr); alias_addr.s_addr = special_addr.s_addr | htonl(CTL_ALIAS); getouraddr(); } #define CONN_CANFSEND(so) (((so)->so_state & (SS_FCANTSENDMORE|SS_ISFCONNECTED)) == SS_ISFCONNECTED) #define CONN_CANFRCV(so) (((so)->so_state & (SS_FCANTRCVMORE|SS_ISFCONNECTED)) == SS_ISFCONNECTED) #define UPD_NFDS(x) if (nfds < (x)) nfds = (x) /* * curtime kept to an accuracy of 1ms */ #ifdef _WIN32 static void updtime(void) { struct _timeb tb; _ftime(&tb); curtime = (u_int)tb.time * (u_int)1000; curtime += (u_int)tb.millitm; } #else static void updtime(void) { gettimeofday(&tt, 0); curtime = (u_int)tt.tv_sec * (u_int)1000; curtime += (u_int)tt.tv_usec / (u_int)1000; if ((tt.tv_usec % 1000) >= 500) curtime++; } #endif void slirp_select_fill(int *pnfds, fd_set *readfds, fd_set *writefds, fd_set *xfds) { struct socket *so, *so_next; struct timeval timeout; int nfds; int tmp_time; /* fail safe */ global_readfds = NULL; global_writefds = NULL; global_xfds = NULL; nfds = *pnfds; /* * First, TCP sockets */ do_slowtimo = 0; if (link_up) { /* * *_slowtimo needs calling if there are IP fragments * in the fragment queue, or there are TCP connections active */ do_slowtimo = ((tcb.so_next != &tcb) || ((struct ipasfrag *)&ipq != (struct ipasfrag *)ipq.next)); for (so = tcb.so_next; so != &tcb; so = so_next) { so_next = so->so_next; /* * See if we need a tcp_fasttimo */ if (time_fasttimo == 0 && so->so_tcpcb->t_flags & TF_DELACK) time_fasttimo = curtime; /* Flag when we want a fasttimo */ /* * NOFDREF can include still connecting to local-host, * newly socreated() sockets etc. Don't want to select these. */ if (so->so_state & SS_NOFDREF || so->s == -1) continue; /* * Set for reading sockets which are accepting */ if (so->so_state & SS_FACCEPTCONN) { FD_SET(so->s, readfds); UPD_NFDS(so->s); continue; } /* * Set for writing sockets which are connecting */ if (so->so_state & SS_ISFCONNECTING) { FD_SET(so->s, writefds); UPD_NFDS(so->s); continue; } /* * Set for writing if we are connected, can send more, and * we have something to send */ if (CONN_CANFSEND(so) && so->so_rcv.sb_cc) { FD_SET(so->s, writefds); UPD_NFDS(so->s); } /* * Set for reading (and urgent data) if we are connected, can * receive more, and we have room for it XXX /2 ? */ if (CONN_CANFRCV(so) && (so->so_snd.sb_cc < (so->so_snd.sb_datalen/2))) { FD_SET(so->s, readfds); FD_SET(so->s, xfds); UPD_NFDS(so->s); } } /* * UDP sockets */ for (so = udb.so_next; so != &udb; so = so_next) { so_next = so->so_next; /* * See if it's timed out */ if (so->so_expire) { if (so->so_expire <= curtime) { udp_detach(so); continue; } else do_slowtimo = 1; /* Let socket expire */ } /* * When UDP packets are received from over the * link, they're sendto()'d straight away, so * no need for setting for writing * Limit the number of packets queued by this session * to 4. Note that even though we try and limit this * to 4 packets, the session could have more queued * if the packets needed to be fragmented * (XXX <= 4 ?) */ if ((so->so_state & SS_ISFCONNECTED) && so->so_queued <= 4) { FD_SET(so->s, readfds); UPD_NFDS(so->s); } } } /* * Setup timeout to use minimum CPU usage, especially when idle */ /* * First, see the timeout needed by *timo */ timeout.tv_sec = 0; timeout.tv_usec = -1; /* * If a slowtimo is needed, set timeout to 500ms from the last * slow timeout. If a fast timeout is needed, set timeout within * 200ms of when it was requested. */ if (do_slowtimo) { /* XXX + 10000 because some select()'s aren't that accurate */ timeout.tv_usec = ((500 - (curtime - last_slowtimo)) * 1000) + 10000; if (timeout.tv_usec < 0) timeout.tv_usec = 0; else if (timeout.tv_usec > 510000) timeout.tv_usec = 510000; /* Can only fasttimo if we also slowtimo */ if (time_fasttimo) { tmp_time = (200 - (curtime - time_fasttimo)) * 1000; if (tmp_time < 0) tmp_time = 0; /* Choose the smallest of the 2 */ if (tmp_time < timeout.tv_usec) timeout.tv_usec = (u_int)tmp_time; } } *pnfds = nfds; } void slirp_select_poll(fd_set *readfds, fd_set *writefds, fd_set *xfds) { struct socket *so, *so_next; int ret; global_readfds = readfds; global_writefds = writefds; global_xfds = xfds; /* Update time */ updtime(); /* * See if anything has timed out */ if (link_up) { if (time_fasttimo && ((curtime - time_fasttimo) >= 2)) { tcp_fasttimo(); time_fasttimo = 0; } if (do_slowtimo && ((curtime - last_slowtimo) >= 499)) { ip_slowtimo(); tcp_slowtimo(); last_slowtimo = curtime; } } /* * Check sockets */ if (link_up) { /* * Check TCP sockets */ for (so = tcb.so_next; so != &tcb; so = so_next) { so_next = so->so_next; /* * FD_ISSET is meaningless on these sockets * (and they can crash the program) */ if (so->so_state & SS_NOFDREF || so->s == -1) continue; /* * Check for URG data * This will soread as well, so no need to * test for readfds below if this succeeds */ if (FD_ISSET(so->s, xfds)) sorecvoob(so); /* * Check sockets for reading */ else if (FD_ISSET(so->s, readfds)) { /* * Check for incoming connections */ if (so->so_state & SS_FACCEPTCONN) { tcp_connect(so); continue; } /* else */ ret = soread(so); /* Output it if we read something */ if (ret > 0) tcp_output(sototcpcb(so)); } /* * Check sockets for writing */ if (FD_ISSET(so->s, writefds)) { /* * Check for non-blocking, still-connecting sockets */ if (so->so_state & SS_ISFCONNECTING) { /* Connected */ so->so_state &= ~SS_ISFCONNECTING; ret = send(so->s, &ret, 0, 0); if (ret < 0) { /* XXXXX Must fix, zero bytes is a NOP */ if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINPROGRESS || errno == ENOTCONN) continue; /* else failed */ so->so_state = SS_NOFDREF; } /* else so->so_state &= ~SS_ISFCONNECTING; */ /* * Continue tcp_input */ tcp_input((struct mbuf *)NULL, sizeof(struct ip), so); /* continue; */ } else ret = sowrite(so); /* * XXXXX If we wrote something (a lot), there * could be a need for a window update. * In the worst case, the remote will send * a window probe to get things going again */ } /* * Probe a still-connecting, non-blocking socket * to check if it's still alive */ #ifdef PROBE_CONN if (so->so_state & SS_ISFCONNECTING) { ret = recv(so->s, (char *)&ret, 0,0); if (ret < 0) { /* XXX */ if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINPROGRESS || errno == ENOTCONN) continue; /* Still connecting, continue */ /* else failed */ so->so_state = SS_NOFDREF; /* tcp_input will take care of it */ } else { ret = send(so->s, &ret, 0,0); if (ret < 0) { /* XXX */ if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINPROGRESS || errno == ENOTCONN) continue; /* else failed */ so->so_state = SS_NOFDREF; } else so->so_state &= ~SS_ISFCONNECTING; } tcp_input((struct mbuf *)NULL, sizeof(struct ip),so); } /* SS_ISFCONNECTING */ #endif } /* * Now UDP sockets. * Incoming packets are sent straight away, they're not buffered. * Incoming UDP data isn't buffered either. */ for (so = udb.so_next; so != &udb; so = so_next) { so_next = so->so_next; if (so->s != -1 && FD_ISSET(so->s, readfds)) { sorecvfrom(so); } } } /* * See if we can start outputting */ if (if_queued && link_up) if_start(); /* clear global file descriptor sets. * these reside on the stack in vl.c * so they're unusable if we're not in * slirp_select_fill or slirp_select_poll. */ global_readfds = NULL; global_writefds = NULL; global_xfds = NULL; } #define ETH_ALEN 6 #define ETH_HLEN 14 #define ETH_P_IP 0x0800 /* Internet Protocol packet */ #define ETH_P_ARP 0x0806 /* Address Resolution packet */ #define ARPOP_REQUEST 1 /* ARP request */ #define ARPOP_REPLY 2 /* ARP reply */ struct ethhdr { unsigned char h_dest[ETH_ALEN]; /* destination eth addr */ unsigned char h_source[ETH_ALEN]; /* source ether addr */ unsigned short h_proto; /* packet type ID field */ }; struct arphdr { unsigned short ar_hrd; /* format of hardware address */ unsigned short ar_pro; /* format of protocol address */ unsigned char ar_hln; /* length of hardware address */ unsigned char ar_pln; /* length of protocol address */ unsigned short ar_op; /* ARP opcode (command) */ /* * Ethernet looks like this : This bit is variable sized however... */ unsigned char ar_sha[ETH_ALEN]; /* sender hardware address */ unsigned char ar_sip[4]; /* sender IP address */ unsigned char ar_tha[ETH_ALEN]; /* target hardware address */ unsigned char ar_tip[4]; /* target IP address */ }; void arp_input(const uint8_t *pkt, int pkt_len) { struct ethhdr *eh = (struct ethhdr *)pkt; struct arphdr *ah = (struct arphdr *)(pkt + ETH_HLEN); uint8_t arp_reply[ETH_HLEN + sizeof(struct arphdr)]; struct ethhdr *reh = (struct ethhdr *)arp_reply; struct arphdr *rah = (struct arphdr *)(arp_reply + ETH_HLEN); int ar_op; struct ex_list *ex_ptr; ar_op = ntohs(ah->ar_op); switch(ar_op) { case ARPOP_REQUEST: if (!memcmp(ah->ar_tip, &special_addr, 3)) { if (ah->ar_tip[3] == CTL_DNS || ah->ar_tip[3] == CTL_ALIAS) goto arp_ok; for (ex_ptr = exec_list; ex_ptr; ex_ptr = ex_ptr->ex_next) { if (ex_ptr->ex_addr == ah->ar_tip[3]) goto arp_ok; } return; arp_ok: /* XXX: make an ARP request to have the client address */ memcpy(client_ethaddr, eh->h_source, ETH_ALEN); /* ARP request for alias/dns mac address */ memcpy(reh->h_dest, pkt + ETH_ALEN, ETH_ALEN); memcpy(reh->h_source, special_ethaddr, ETH_ALEN - 1); reh->h_source[5] = ah->ar_tip[3]; reh->h_proto = htons(ETH_P_ARP); rah->ar_hrd = htons(1); rah->ar_pro = htons(ETH_P_IP); rah->ar_hln = ETH_ALEN; rah->ar_pln = 4; rah->ar_op = htons(ARPOP_REPLY); memcpy(rah->ar_sha, reh->h_source, ETH_ALEN); memcpy(rah->ar_sip, ah->ar_tip, 4); memcpy(rah->ar_tha, ah->ar_sha, ETH_ALEN); memcpy(rah->ar_tip, ah->ar_sip, 4); slirp_output(arp_reply, sizeof(arp_reply)); } break; default: break; } } void slirp_input(const uint8_t *pkt, int pkt_len) { struct mbuf *m; int proto; if (pkt_len < ETH_HLEN) return; proto = ntohs(*(uint16_t *)(pkt + 12)); switch(proto) { case ETH_P_ARP: arp_input(pkt, pkt_len); break; case ETH_P_IP: m = m_get(); if (!m) return; /* Note: we add to align the IP header */ m->m_len = pkt_len + 2; memcpy(m->m_data + 2, pkt, pkt_len); m->m_data += 2 + ETH_HLEN; m->m_len -= 2 + ETH_HLEN; ip_input(m); break; default: break; } } /* output the IP packet to the ethernet device */ void if_encap(const uint8_t *ip_data, int ip_data_len) { uint8_t buf[1600]; struct ethhdr *eh = (struct ethhdr *)buf; if (ip_data_len + ETH_HLEN > sizeof(buf)) return; memcpy(eh->h_dest, client_ethaddr, ETH_ALEN); memcpy(eh->h_source, special_ethaddr, ETH_ALEN - 1); /* XXX: not correct */ eh->h_source[5] = CTL_ALIAS; eh->h_proto = htons(ETH_P_IP); memcpy(buf + sizeof(struct ethhdr), ip_data, ip_data_len); slirp_output(buf, ip_data_len + ETH_HLEN); } int slirp_redir(int is_udp, int host_port, struct in_addr guest_addr, int guest_port) { if (is_udp) { if (!udp_listen(htons(host_port), guest_addr.s_addr, htons(guest_port), 0)) return -1; } else { if (!solisten(htons(host_port), guest_addr.s_addr, htons(guest_port), 0)) return -1; } return 0; } int slirp_add_exec(int do_pty, const char *args, int addr_low_byte, int guest_port) { return add_exec(&exec_list, do_pty, (char *)args, addr_low_byte, htons(guest_port)); }