udp_emu(struct socket *so, struct mbuf *m) { struct sockaddr_in addr; int addrlen = sizeof(addr); #ifdef EMULATE_TALK CTL_MSG_OLD *omsg; CTL_MSG *nmsg; char buff[sizeof(CTL_MSG)]; u_char type; struct talk_request { struct talk_request *next; struct socket *udp_so; struct socket *tcp_so; } *req; static struct talk_request *req_tbl = 0; #endif struct cu_header { uint16_t d_family; // destination family uint16_t d_port; // destination port uint32_t d_addr; // destination address uint16_t s_family; // source family uint16_t s_port; // source port uint32_t so_addr; // source address uint32_t seqn; // sequence number uint16_t message; // message uint16_t data_type; // data type uint16_t pkt_len; // packet length } *cu_head; switch(so->so_emu) { #ifdef EMULATE_TALK case EMU_TALK: case EMU_NTALK: /* * Talk emulation. We always change the ctl_addr to get * some answers from the daemon. When an ANNOUNCE comes, * we send LEAVE_INVITE to the local daemons. Also when a * DELETE comes, we send copies to the local daemons. */ if (getsockname(so->s, (struct sockaddr *)&addr, &addrlen) < 0) return; #define IS_OLD (so->so_emu == EMU_TALK) #define COPY_MSG(dest, src) { dest->type = src->type; \ dest->id_num = src->id_num; \ dest->pid = src->pid; \ dest->addr = src->addr; \ dest->ctl_addr = src->ctl_addr; \ memcpy(&dest->l_name, &src->l_name, NAME_SIZE_OLD); \ memcpy(&dest->r_name, &src->r_name, NAME_SIZE_OLD); \ memcpy(&dest->r_tty, &src->r_tty, TTY_SIZE); } #define OTOSIN(ptr, field) ((struct sockaddr_in *)&ptr->field) /* old_sockaddr to sockaddr_in */ if (IS_OLD) { /* old talk */ omsg = mtod(m, CTL_MSG_OLD*); nmsg = (CTL_MSG *) buff; type = omsg->type; OTOSIN(omsg, ctl_addr)->sin_port = addr.sin_port; OTOSIN(omsg, ctl_addr)->sin_addr = our_addr; strncpy(omsg->l_name, getlogin(), NAME_SIZE_OLD); } else { /* new talk */ omsg = (CTL_MSG_OLD *) buff; nmsg = mtod(m, CTL_MSG *); type = nmsg->type; OTOSIN(nmsg, ctl_addr)->sin_port = addr.sin_port; OTOSIN(nmsg, ctl_addr)->sin_addr = our_addr; strncpy(nmsg->l_name, getlogin(), NAME_SIZE_OLD); } if (type == LOOK_UP) return; /* for LOOK_UP this is enough */ if (IS_OLD) { /* make a copy of the message */ COPY_MSG(nmsg, omsg); nmsg->vers = 1; nmsg->answer = 0; } else COPY_MSG(omsg, nmsg); /* * If if is an ANNOUNCE message, we go through the * request table to see if a tcp port has already * been redirected for this socket. If not, we solisten() * a new socket and add this entry to the table. * The port number of the tcp socket and our IP * are put to the addr field of the message structures. * Then a LEAVE_INVITE is sent to both local daemon * ports, 517 and 518. This is why we have two copies * of the message, one in old talk and one in new talk * format. */ if (type == ANNOUNCE) { int s; u_short temp_port; for(req = req_tbl; req; req = req->next) if (so == req->udp_so) break; /* found it */ if (!req) { /* no entry for so, create new */ req = (struct talk_request *) malloc(sizeof(struct talk_request)); req->udp_so = so; req->tcp_so = solisten(0, OTOSIN(omsg, addr)->sin_addr.s_addr, OTOSIN(omsg, addr)->sin_port, SS_FACCEPTONCE); req->next = req_tbl; req_tbl = req; } /* replace port number in addr field */ addrlen = sizeof(addr); getsockname(req->tcp_so->s, (struct sockaddr *) &addr, &addrlen); OTOSIN(omsg, addr)->sin_port = addr.sin_port; OTOSIN(omsg, addr)->sin_addr = our_addr; OTOSIN(nmsg, addr)->sin_port = addr.sin_port; OTOSIN(nmsg, addr)->sin_addr = our_addr; /* send LEAVE_INVITEs */ temp_port = OTOSIN(omsg, ctl_addr)->sin_port; OTOSIN(omsg, ctl_addr)->sin_port = 0; OTOSIN(nmsg, ctl_addr)->sin_port = 0; omsg->type = nmsg->type = LEAVE_INVITE; s = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP); addr.sin_addr = our_addr; addr.sin_family = AF_INET; addr.sin_port = htons(517); sendto(s, (char *)omsg, sizeof(*omsg), 0, (struct sockaddr *)&addr, sizeof(addr)); addr.sin_port = htons(518); sendto(s, (char *)nmsg, sizeof(*nmsg), 0, (struct sockaddr *) &addr, sizeof(addr)); closesocket(s) ; omsg->type = nmsg->type = ANNOUNCE; OTOSIN(omsg, ctl_addr)->sin_port = temp_port; OTOSIN(nmsg, ctl_addr)->sin_port = temp_port; } /* * If it is a DELETE message, we send a copy to the * local daemons. Then we delete the entry corresponding * to our socket from the request table. */ if (type == DELETE) { struct talk_request *temp_req, *req_next; int s; u_short temp_port; temp_port = OTOSIN(omsg, ctl_addr)->sin_port; OTOSIN(omsg, ctl_addr)->sin_port = 0; OTOSIN(nmsg, ctl_addr)->sin_port = 0; s = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP); addr.sin_addr = our_addr; addr.sin_family = AF_INET; addr.sin_port = htons(517); sendto(s, (char *)omsg, sizeof(*omsg), 0, (struct sockaddr *)&addr, sizeof(addr)); addr.sin_port = htons(518); sendto(s, (char *)nmsg, sizeof(*nmsg), 0, (struct sockaddr *)&addr, sizeof(addr)); closesocket(s); OTOSIN(omsg, ctl_addr)->sin_port = temp_port; OTOSIN(nmsg, ctl_addr)->sin_port = temp_port; /* delete table entry */ if (so == req_tbl->udp_so) { temp_req = req_tbl; req_tbl = req_tbl->next; free(temp_req); } else { temp_req = req_tbl; for(req = req_tbl->next; req; req = req_next) { req_next = req->next; if (so == req->udp_so) { temp_req->next = req_next; free(req); break; } else { temp_req = req; } } } } return; #endif case EMU_CUSEEME: /* * Cu-SeeMe emulation. * Hopefully the packet is more that 16 bytes long. We don't * do any other tests, just replace the address and port * fields. */ if (m->m_len >= sizeof (*cu_head)) { if (getsockname(so->s, (struct sockaddr *)&addr, &addrlen) < 0) return; cu_head = mtod(m, struct cu_header *); cu_head->s_port = addr.sin_port; cu_head->so_addr = our_addr.s_addr; } return; } }