1 /* tcp_subr.c 4.26 82/04/30 */ 2 3 #include "../h/param.h" 4 #include "../h/systm.h" 5 #include "../h/mbuf.h" 6 #include "../h/socket.h" 7 #include "../h/socketvar.h" 8 #include "../h/protosw.h" 9 #include "../net/in.h" 10 #include "../net/route.h" 11 #include "../net/in_pcb.h" 12 #include "../net/in_systm.h" 13 #include "../net/if.h" 14 #include "../net/ip.h" 15 #include "../net/ip_var.h" 16 #include "../net/ip_icmp.h" 17 #include "../net/tcp.h" 18 #include "../net/tcp_fsm.h" 19 #include "../net/tcp_seq.h" 20 #include "../net/tcp_timer.h" 21 #include "../net/tcp_var.h" 22 #include "../net/tcpip.h" 23 #include "../errno.h" 24 25 /* 26 * Tcp initialization 27 */ 28 tcp_init() 29 { 30 31 COUNT(TCP_INIT); 32 tcp_iss = 1; /* wrong */ 33 tcb.inp_next = tcb.inp_prev = &tcb; 34 tcp_alpha = TCP_ALPHA; 35 tcp_beta = TCP_BETA; 36 } 37 38 /* 39 * Create template to be used to send tcp packets on a connection. 40 * Call after host entry created, allocates an mbuf and fills 41 * in a skeletal tcp/ip header, minimizing the amount of work 42 * necessary when the connection is used. 43 */ 44 struct tcpiphdr * 45 tcp_template(tp) 46 struct tcpcb *tp; 47 { 48 register struct inpcb *inp = tp->t_inpcb; 49 register struct mbuf *m; 50 register struct tcpiphdr *n; 51 52 COUNT(TCP_TEMPLATE); 53 m = m_get(M_WAIT); 54 if (m == 0) 55 return (0); 56 m->m_off = MMAXOFF - sizeof (struct tcpiphdr); 57 m->m_len = sizeof (struct tcpiphdr); 58 n = mtod(m, struct tcpiphdr *); 59 n->ti_next = n->ti_prev = 0; 60 n->ti_x1 = 0; 61 n->ti_pr = IPPROTO_TCP; 62 n->ti_len = htons(sizeof (struct tcpiphdr) - sizeof (struct ip)); 63 n->ti_src = inp->inp_laddr; 64 n->ti_dst = inp->inp_faddr; 65 n->ti_sport = inp->inp_lport; 66 n->ti_dport = inp->inp_fport; 67 n->ti_seq = 0; 68 n->ti_ack = 0; 69 n->ti_x2 = 0; 70 n->ti_off = 5; 71 n->ti_flags = 0; 72 n->ti_win = 0; 73 n->ti_sum = 0; 74 n->ti_urp = 0; 75 return (n); 76 } 77 78 /* 79 * Send a single message to the TCP at address specified by 80 * the given TCP/IP header. If flags==0, then we make a copy 81 * of the tcpiphdr at ti and send directly to the addressed host. 82 * This is used to force keep alive messages out using the TCP 83 * template for a connection tp->t_template. If flags are given 84 * then we send a message back to the TCP which originated the 85 * segment ti, and discard the mbuf containing it and any other 86 * attached mbufs. 87 * 88 * In any case the ack and sequence number of the transmitted 89 * segment are as specified by the parameters. 90 */ 91 tcp_respond(tp, ti, ack, seq, flags) 92 struct tcpcb *tp; 93 register struct tcpiphdr *ti; 94 tcp_seq ack, seq; 95 int flags; 96 { 97 struct mbuf *m; 98 int win = 0, tlen; 99 struct route *ro = 0; 100 101 COUNT(TCP_RESPOND); 102 if (tp) { 103 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv); 104 ro = &tp->t_inpcb->inp_route; 105 } 106 if (flags == 0) { 107 m = m_get(M_DONTWAIT); 108 if (m == 0) 109 return; 110 m->m_off = MMINOFF; 111 m->m_len = sizeof (struct tcpiphdr) + 1; 112 *mtod(m, struct tcpiphdr *) = *ti; 113 ti = mtod(m, struct tcpiphdr *); 114 flags = TH_ACK; 115 tlen = 1; 116 } else { 117 m = dtom(ti); 118 m_freem(m->m_next); 119 m->m_next = 0; 120 m->m_off = (int)ti - (int)m; 121 m->m_len = sizeof (struct tcpiphdr); 122 #define xchg(a,b,type) { type t; t=a; a=b; b=t; } 123 xchg(ti->ti_dst.s_addr, ti->ti_src.s_addr, u_long); 124 xchg(ti->ti_dport, ti->ti_sport, u_short); 125 #undef xchg 126 tlen = 0; 127 } 128 ti->ti_next = ti->ti_prev = 0; 129 ti->ti_x1 = 0; 130 ti->ti_len = sizeof (struct tcphdr) + tlen; 131 ti->ti_seq = seq; 132 ti->ti_ack = ack; 133 #if vax 134 ti->ti_len = htons((u_short)ti->ti_len); 135 ti->ti_seq = htonl(ti->ti_seq); 136 ti->ti_ack = htonl(ti->ti_ack); 137 #endif 138 ti->ti_x2 = 0; 139 ti->ti_off = sizeof (struct tcphdr) >> 2; 140 ti->ti_flags = flags; 141 ti->ti_win = win; 142 #if vax 143 ti->ti_win = htons(ti->ti_win); 144 #endif 145 ti->ti_urp = 0; 146 ti->ti_sum = in_cksum(m, sizeof (struct tcpiphdr) + tlen); 147 ((struct ip *)ti)->ip_len = sizeof (struct tcpiphdr) + tlen; 148 ((struct ip *)ti)->ip_ttl = TCP_TTL; 149 (void) ip_output(m, (struct mbuf *)0, ro, 0); 150 } 151 152 /* 153 * Create a new TCP control block, making an 154 * empty reassembly queue and hooking it to the argument 155 * protocol control block. 156 */ 157 struct tcpcb * 158 tcp_newtcpcb(inp) 159 struct inpcb *inp; 160 { 161 struct mbuf *m = m_getclr(M_DONTWAIT); 162 register struct tcpcb *tp; 163 COUNT(TCP_NEWTCPCB); 164 165 if (m == 0) 166 return (0); 167 tp = mtod(m, struct tcpcb *); 168 tp->seg_next = tp->seg_prev = (struct tcpiphdr *)tp; 169 tp->t_maxseg = 576; /* satisfy the rest of the world */ 170 tp->t_flags = 0; /* sends options! */ 171 tp->t_inpcb = inp; 172 inp->inp_ppcb = (caddr_t)tp; 173 return (tp); 174 } 175 176 /* 177 * Drop a TCP connection, reporting 178 * the specified error. If connection is synchronized, 179 * then send a RST to peer. 180 */ 181 tcp_drop(tp, errno) 182 struct tcpcb *tp; 183 int errno; 184 { 185 struct socket *so = tp->t_inpcb->inp_socket; 186 187 COUNT(TCP_DROP); 188 if (TCPS_HAVERCVDSYN(tp->t_state)) { 189 tp->t_state = TCPS_CLOSED; 190 tcp_output(tp); 191 } 192 so->so_error = errno; 193 tcp_close(tp); 194 } 195 196 tcp_abort(inp) 197 struct inpcb *inp; 198 { 199 tcp_close(inp->inp_ppcb); 200 } 201 202 /* 203 * Close a TCP control block: 204 * discard all space held by the tcp 205 * discard internet protocol block 206 * wake up any sleepers 207 */ 208 tcp_close(tp) 209 register struct tcpcb *tp; 210 { 211 register struct tcpiphdr *t; 212 struct inpcb *inp = tp->t_inpcb; 213 struct socket *so = inp->inp_socket; 214 215 COUNT(TCP_CLOSE); 216 t = tp->seg_next; 217 for (; t != (struct tcpiphdr *)tp; t = (struct tcpiphdr *)t->ti_next) 218 m_freem(dtom(t)); 219 if (tp->t_template) 220 (void) m_free(dtom(tp->t_template)); 221 if (tp->t_tcpopt) 222 (void) m_free(dtom(tp->t_tcpopt)); 223 if (tp->t_ipopt) 224 (void) m_free(dtom(tp->t_ipopt)); 225 (void) m_free(dtom(tp)); 226 inp->inp_ppcb = 0; 227 soisdisconnected(so); 228 in_pcbdetach(inp); 229 } 230 231 tcp_drain() 232 { 233 234 COUNT(TCP_DRAIN); 235 } 236 237 tcp_ctlinput(cmd, arg) 238 int cmd; 239 caddr_t arg; 240 { 241 struct in_addr *sin; 242 extern u_char inetctlerrmap[]; 243 COUNT(TCP_CTLINPUT); 244 245 if (cmd < 0 || cmd > PRC_NCMDS) 246 return; 247 switch (cmd) { 248 249 case PRC_ROUTEDEAD: 250 break; 251 252 case PRC_QUENCH: 253 break; 254 255 /* these are handled by ip */ 256 case PRC_IFDOWN: 257 case PRC_HOSTDEAD: 258 case PRC_HOSTUNREACH: 259 break; 260 261 default: 262 sin = &((struct icmp *)arg)->icmp_ip.ip_dst; 263 in_pcbnotify(&tcb, sin, inetctlerrmap[cmd], tcp_abort); 264 } 265 } 266