4.1cBSD/a/sys/netinet/tcp_usrreq.c
/* tcp_usrreq.c 1.75 83/02/22 */
#include "../h/param.h"
#include "../h/systm.h"
#include "../h/mbuf.h"
#include "../h/socket.h"
#include "../h/socketvar.h"
#include "../h/protosw.h"
#include "../h/errno.h"
#include "../net/if.h"
#include "../net/route.h"
#include "../netinet/in.h"
#include "../netinet/in_pcb.h"
#include "../netinet/in_systm.h"
#include "../netinet/ip.h"
#include "../netinet/ip_var.h"
#include "../netinet/tcp.h"
#include "../netinet/tcp_fsm.h"
#include "../netinet/tcp_seq.h"
#include "../netinet/tcp_timer.h"
#include "../netinet/tcp_var.h"
#include "../netinet/tcpip.h"
#include "../netinet/tcp_debug.h"
/*
* TCP protocol interface to socket abstraction.
*/
extern char *tcpstates[];
struct tcpcb *tcp_newtcpcb();
/*
* Process a TCP user request for TCP tb. If this is a send request
* then m is the mbuf chain of send data. If this is a timer expiration
* (called from the software clock routine), then timertype tells which timer.
*/
/*ARGSUSED*/
tcp_usrreq(so, req, m, nam)
struct socket *so;
int req;
struct mbuf *m, *nam;
{
register struct inpcb *inp = sotoinpcb(so);
register struct tcpcb *tp;
int s = splnet();
int error = 0;
int ostate;
/*
* When a TCP is attached to a socket, then there will be
* a (struct inpcb) pointed at by the socket, and this
* structure will point at a subsidary (struct tcpcb).
*/
if (inp == 0 && req != PRU_ATTACH) {
splx(s);
return (EINVAL); /* XXX */
}
if (inp) {
tp = intotcpcb(inp);
/* WHAT IF TP IS 0? */
#ifdef KPROF
tcp_acounts[tp->t_state][req]++;
#endif
ostate = tp->t_state;
} else
ostate = 0;
switch (req) {
/*
* TCP attaches to socket via PRU_ATTACH, reserving space,
* and an internet control block.
*/
case PRU_ATTACH:
if (inp) {
error = EISCONN;
break;
}
error = tcp_attach(so);
if (error)
break;
if ((so->so_options & SO_LINGER) && so->so_linger == 0)
so->so_linger = TCP_LINGERTIME;
tp = sototcpcb(so);
break;
/*
* PRU_DETACH detaches the TCP protocol from the socket.
* If the protocol state is non-embryonic, then can't
* do this directly: have to initiate a PRU_DISCONNECT,
* which may finish later; embryonic TCB's can just
* be discarded here.
*/
case PRU_DETACH:
if (tp->t_state > TCPS_LISTEN)
tp = tcp_disconnect(tp);
else
tp = tcp_close(tp);
break;
/*
* Give the socket an address.
*/
case PRU_BIND:
error = in_pcbbind(inp, nam);
if (error)
break;
break;
/*
* Prepare to accept connections.
*/
case PRU_LISTEN:
if (inp->inp_lport == 0)
error = in_pcbbind(inp, (struct mbuf *)0);
if (error == 0)
tp->t_state = TCPS_LISTEN;
break;
/*
* Initiate connection to peer.
* Create a template for use in transmissions on this connection.
* Enter SYN_SENT state, and mark socket as connecting.
* Start keep-alive timer, and seed output sequence space.
* Send initial segment on connection.
*/
case PRU_CONNECT:
if (inp->inp_lport == 0) {
error = in_pcbbind(inp, (struct mbuf *)0);
if (error)
break;
}
error = in_pcbconnect(inp, nam);
if (error)
break;
tp->t_template = tcp_template(tp);
if (tp->t_template == 0) {
in_pcbdisconnect(inp);
error = ENOBUFS;
break;
}
soisconnecting(so);
tp->t_state = TCPS_SYN_SENT;
tp->t_timer[TCPT_KEEP] = TCPTV_KEEP;
tp->iss = tcp_iss; tcp_iss += TCP_ISSINCR/2;
tcp_sendseqinit(tp);
error = tcp_output(tp);
break;
/*
* Initiate disconnect from peer.
* If connection never passed embryonic stage, just drop;
* else if don't need to let data drain, then can just drop anyways,
* else have to begin TCP shutdown process: mark socket disconnecting,
* drain unread data, state switch to reflect user close, and
* send segment (e.g. FIN) to peer. Socket will be really disconnected
* when peer sends FIN and acks ours.
*
* SHOULD IMPLEMENT LATER PRU_CONNECT VIA REALLOC TCPCB.
*/
case PRU_DISCONNECT:
tp = tcp_disconnect(tp);
break;
/*
* Accept a connection. Essentially all the work is
* done at higher levels; just return the address
* of the peer, storing through addr.
*/
case PRU_ACCEPT: {
struct sockaddr_in *sin = mtod(nam, struct sockaddr_in *);
nam->m_len = sizeof (struct sockaddr_in);
sin->sin_family = AF_INET;
sin->sin_port = inp->inp_fport;
sin->sin_addr = inp->inp_faddr;
break;
}
/*
* Mark the connection as being incapable of further output.
*/
case PRU_SHUTDOWN:
socantsendmore(so);
tp = tcp_usrclosed(tp);
if (tp)
error = tcp_output(tp);
break;
/*
* After a receive, possibly send window update to peer.
*/
case PRU_RCVD:
(void) tcp_output(tp);
break;
/*
* Do a send by putting data in output queue and updating urgent
* marker if URG set. Possibly send more data.
*/
case PRU_SEND:
sbappend(&so->so_snd, m);
#ifdef notdef
if (tp->t_flags & TF_PUSH)
tp->snd_end = tp->snd_una + so->so_snd.sb_cc;
#endif
error = tcp_output(tp);
break;
/*
* Abort the TCP.
*/
case PRU_ABORT:
tp = tcp_drop(tp, ECONNABORTED);
break;
/* SOME AS YET UNIMPLEMENTED HOOKS */
case PRU_CONTROL:
error = EOPNOTSUPP;
break;
case PRU_SENSE:
error = EOPNOTSUPP;
break;
/* END UNIMPLEMENTED HOOKS */
case PRU_RCVOOB:
if (so->so_oobmark == 0 &&
(so->so_state & SS_RCVATMARK) == 0) {
error = EINVAL;
break;
}
if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) {
error = EWOULDBLOCK;
break;
}
m->m_len = 1;
*mtod(m, caddr_t) = tp->t_iobc;
break;
case PRU_SENDOOB:
if (sbspace(&so->so_snd) < -512) {
m_freem(m);
error = ENOBUFS;
break;
}
tp->snd_up = tp->snd_una + so->so_snd.sb_cc + 1;
sbappend(&so->so_snd, m);
tp->t_force = 1;
error = tcp_output(tp);
tp->t_force = 0;
break;
case PRU_SOCKADDR:
in_setsockaddr(inp, nam);
break;
/*
* TCP slow timer went off; going through this
* routine for tracing's sake.
*/
case PRU_SLOWTIMO:
tp = tcp_timers(tp, (int)nam);
req |= (int)nam << 8; /* for debug's sake */
break;
default:
panic("tcp_usrreq");
}
if (tp && (so->so_options & SO_DEBUG))
tcp_trace(TA_USER, ostate, tp, (struct tcpiphdr *)0, req);
splx(s);
return (error);
}
int tcp_sendspace = 1024*2;
int tcp_recvspace = 1024*2;
/*
* Attach TCP protocol to socket, allocating
* internet protocol control block, tcp control block,
* bufer space, and entering LISTEN state if to accept connections.
*/
tcp_attach(so)
struct socket *so;
{
register struct tcpcb *tp;
struct inpcb *inp;
int error;
error = soreserve(so, tcp_sendspace, tcp_recvspace);
if (error)
goto bad;
error = in_pcballoc(so, &tcb);
if (error)
goto bad;
inp = sotoinpcb(so);
tp = tcp_newtcpcb(inp);
if (tp == 0) {
error = ENOBUFS;
goto bad2;
}
tp->t_state = TCPS_CLOSED;
return (0);
bad2:
in_pcbdetach(inp);
bad:
return (error);
}
/*
* Initiate (or continue) disconnect.
* If embryonic state, just send reset (once).
* If not in ``let data drain'' option, just drop.
* Otherwise (hard), mark socket disconnecting and drop
* current input data; switch states based on user close, and
* send segment to peer (with FIN).
*/
struct tcpcb *
tcp_disconnect(tp)
register struct tcpcb *tp;
{
struct socket *so = tp->t_inpcb->inp_socket;
if (tp->t_state < TCPS_ESTABLISHED)
tp = tcp_close(tp);
else if (so->so_linger == 0)
tp = tcp_drop(tp, 0);
else {
soisdisconnecting(so);
sbflush(&so->so_rcv);
tp = tcp_usrclosed(tp);
if (tp)
(void) tcp_output(tp);
}
return (tp);
}
/*
* User issued close, and wish to trail through shutdown states:
* if never received SYN, just forget it. If got a SYN from peer,
* but haven't sent FIN, then go to FIN_WAIT_1 state to send peer a FIN.
* If already got a FIN from peer, then almost done; go to LAST_ACK
* state. In all other cases, have already sent FIN to peer (e.g.
* after PRU_SHUTDOWN), and just have to play tedious game waiting
* for peer to send FIN or not respond to keep-alives, etc.
* We can let the user exit from the close as soon as the FIN is acked.
*/
struct tcpcb *
tcp_usrclosed(tp)
register struct tcpcb *tp;
{
switch (tp->t_state) {
case TCPS_LISTEN:
case TCPS_SYN_SENT:
tp->t_state = TCPS_CLOSED;
tp = tcp_close(tp);
break;
case TCPS_SYN_RECEIVED:
case TCPS_ESTABLISHED:
tp->t_state = TCPS_FIN_WAIT_1;
break;
case TCPS_CLOSE_WAIT:
tp->t_state = TCPS_LAST_ACK;
break;
}
if (tp && tp->t_state >= TCPS_FIN_WAIT_2)
soisdisconnected(tp->t_inpcb->inp_socket);
return (tp);
}