| 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 | } |