1 /* tcp_subr.c 4.23 82/04/04 */ 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/tcp.h" 17 #include "../net/tcp_fsm.h" 18 #include "../net/tcp_seq.h" 19 #include "../net/tcp_timer.h" 20 #include "../net/tcp_var.h" 21 #include "../net/tcpip.h" 22 #include "../errno.h" 23 24 /* 25 * Tcp initialization 26 */ 27 tcp_init() 28 { 29 30 COUNT(TCP_INIT); 31 tcp_iss = 1; /* wrong */ 32 tcb.inp_next = tcb.inp_prev = &tcb; 33 tcp_alpha = TCP_ALPHA; 34 tcp_beta = TCP_BETA; 35 } 36 37 /* 38 * Create template to be used to send tcp packets on a connection. 39 * Call after host entry created, allocates an mbuf and fills 40 * in a skeletal tcp/ip header, minimizing the amount of work 41 * necessary when the connection is used. 42 */ 43 struct tcpiphdr * 44 tcp_template(tp) 45 struct tcpcb *tp; 46 { 47 register struct inpcb *inp = tp->t_inpcb; 48 register struct mbuf *m; 49 register struct tcpiphdr *n; 50 51 COUNT(TCP_TEMPLATE); 52 m = m_get(M_WAIT); 53 if (m == 0) 54 return (0); 55 m->m_off = MMAXOFF - sizeof (struct tcpiphdr); 56 m->m_len = sizeof (struct tcpiphdr); 57 n = mtod(m, struct tcpiphdr *); 58 n->ti_next = n->ti_prev = 0; 59 n->ti_x1 = 0; 60 n->ti_pr = IPPROTO_TCP; 61 n->ti_len = htons(sizeof (struct tcpiphdr) - sizeof (struct ip)); 62 n->ti_src = inp->inp_laddr; 63 n->ti_dst = inp->inp_faddr; 64 n->ti_sport = inp->inp_lport; 65 n->ti_dport = inp->inp_fport; 66 n->ti_seq = 0; 67 n->ti_ack = 0; 68 n->ti_x2 = 0; 69 n->ti_off = 5; 70 n->ti_flags = 0; 71 n->ti_win = 0; 72 n->ti_sum = 0; 73 n->ti_urp = 0; 74 return (n); 75 } 76 77 /* 78 * Send a single message to the TCP at address specified by 79 * the given TCP/IP header. If flags==0, then we make a copy 80 * of the tcpiphdr at ti and send directly to the addressed host. 81 * This is used to force keep alive messages out using the TCP 82 * template for a connection tp->t_template. If flags are given 83 * then we send a message back to the TCP which originated the 84 * segment ti, and discard the mbuf containing it and any other 85 * attached mbufs. 86 * 87 * In any case the ack and sequence number of the transmitted 88 * segment are as specified by the parameters. 89 */ 90 tcp_respond(tp, ti, ack, seq, flags) 91 struct tcpcb *tp; 92 register struct tcpiphdr *ti; 93 tcp_seq ack, seq; 94 int flags; 95 { 96 struct mbuf *m; 97 int win = 0, tlen; 98 struct route *ro = 0; 99 100 COUNT(TCP_RESPOND); 101 if (tp) { 102 win = sbspace(&tp->t_inpcb->inp_socket->so_rcv); 103 ro = &tp->t_inpcb->inp_route; 104 } 105 if (flags == 0) { 106 m = m_get(M_DONTWAIT); 107 if (m == 0) 108 return; 109 m->m_off = MMINOFF; 110 m->m_len = sizeof (struct tcpiphdr) + 1; 111 *mtod(m, struct tcpiphdr *) = *ti; 112 ti = mtod(m, struct tcpiphdr *); 113 flags = TH_ACK; 114 tlen = 1; 115 } else { 116 m = dtom(ti); 117 m_freem(m->m_next); 118 m->m_next = 0; 119 m->m_off = (int)ti - (int)m; 120 m->m_len = sizeof (struct tcpiphdr); 121 #define xchg(a,b,type) { type t; t=a; a=b; b=t; } 122 xchg(ti->ti_dst.s_addr, ti->ti_src.s_addr, u_long); 123 xchg(ti->ti_dport, ti->ti_sport, u_short); 124 #undef xchg 125 tlen = 0; 126 } 127 ti->ti_next = ti->ti_prev = 0; 128 ti->ti_x1 = 0; 129 ti->ti_len = sizeof (struct tcphdr) + tlen; 130 ti->ti_seq = seq; 131 ti->ti_ack = ack; 132 #if vax 133 ti->ti_len = htons((u_short)ti->ti_len); 134 ti->ti_seq = htonl(ti->ti_seq); 135 ti->ti_ack = htonl(ti->ti_ack); 136 #endif 137 ti->ti_x2 = 0; 138 ti->ti_off = sizeof (struct tcphdr) >> 2; 139 ti->ti_flags = flags; 140 ti->ti_win = win; 141 #if vax 142 ti->ti_win = htons(ti->ti_win); 143 #endif 144 ti->ti_urp = 0; 145 ti->ti_sum = in_cksum(m, sizeof (struct tcpiphdr) + tlen); 146 ((struct ip *)ti)->ip_len = sizeof (struct tcpiphdr) + tlen; 147 ((struct ip *)ti)->ip_ttl = TCP_TTL; 148 (void) ip_output(m, (struct mbuf *)0, ro, 0); 149 } 150 151 /* 152 * Create a new TCP control block, making an 153 * empty reassembly queue and hooking it to the argument 154 * protocol control block. 155 */ 156 struct tcpcb * 157 tcp_newtcpcb(inp) 158 struct inpcb *inp; 159 { 160 struct mbuf *m = m_getclr(M_DONTWAIT); 161 register struct tcpcb *tp; 162 COUNT(TCP_NEWTCPCB); 163 164 if (m == 0) 165 return (0); 166 tp = mtod(m, struct tcpcb *); 167 tp->seg_next = tp->seg_prev = (struct tcpiphdr *)tp; 168 tp->t_maxseg = 1024; 169 tp->t_flags = 0; /* sends options! */ 170 tp->t_inpcb = inp; 171 inp->inp_ppcb = (caddr_t)tp; 172 return (tp); 173 } 174 175 /* 176 * Drop a TCP connection, reporting 177 * the specified error. If connection is synchronized, 178 * then send a RST to peer. 179 */ 180 tcp_drop(tp, errno) 181 struct tcpcb *tp; 182 int errno; 183 { 184 struct socket *so = tp->t_inpcb->inp_socket; 185 186 COUNT(TCP_DROP); 187 if (TCPS_HAVERCVDSYN(tp->t_state)) { 188 tp->t_state = TCPS_CLOSED; 189 tcp_output(tp); 190 } 191 so->so_error = errno; 192 tcp_close(tp); 193 } 194 195 /* 196 * Close a TCP control block: 197 * discard all space held by the tcp 198 * discard internet protocol block 199 * wake up any sleepers 200 */ 201 tcp_close(tp) 202 register struct tcpcb *tp; 203 { 204 register struct tcpiphdr *t; 205 struct inpcb *inp = tp->t_inpcb; 206 struct socket *so = inp->inp_socket; 207 208 COUNT(TCP_CLOSE); 209 t = tp->seg_next; 210 for (; t != (struct tcpiphdr *)tp; t = (struct tcpiphdr *)t->ti_next) 211 m_freem(dtom(t)); 212 if (tp->t_template) 213 (void) m_free(dtom(tp->t_template)); 214 if (tp->t_tcpopt) 215 (void) m_free(dtom(tp->t_tcpopt)); 216 if (tp->t_ipopt) 217 (void) m_free(dtom(tp->t_ipopt)); 218 (void) m_free(dtom(tp)); 219 inp->inp_ppcb = 0; 220 soisdisconnected(so); 221 in_pcbdetach(inp); 222 } 223 224 tcp_drain() 225 { 226 227 COUNT(TCP_DRAIN); 228 } 229 230 tcp_ctlinput(m) 231 struct mbuf *m; 232 { 233 234 COUNT(TCP_CTLINPUT); 235 m_freem(m); 236 } 237