HardenedBSD/sys/netinet/tcp_usrreq.c
Garrett Wollman a29f300e80 The long-awaited mega-massive-network-code- cleanup. Part I.
This commit includes the following changes:
1) Old-style (pr_usrreq()) protocols are no longer supported, the compatibility
glue for them is deleted, and the kernel will panic on boot if any are compiled
in.

2) Certain protocol entry points are modified to take a process structure,
so they they can easily tell whether or not it is possible to sleep, and
also to access credentials.

3) SS_PRIV is no more, and with it goes the SO_PRIVSTATE setsockopt()
call.  Protocols should use the process pointer they are now passed.

4) The PF_LOCAL and PF_ROUTE families have been updated to use the new
style, as has the `raw' skeleton family.

5) PF_LOCAL sockets now obey the process's umask when creating a socket
in the filesystem.

As a result, LINT is now broken.  I'm hoping that some enterprising hacker
with a bit more time will either make the broken bits work (should be
easy for netipx) or dike them out.
1997-04-27 20:01:29 +00:00

793 lines
19 KiB
C

/*
* Copyright (c) 1982, 1986, 1988, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* From: @(#)tcp_usrreq.c 8.2 (Berkeley) 1/3/94
* $Id: tcp_usrreq.c,v 1.30 1997/02/21 16:30:31 wollman Exp $
*/
#include <sys/param.h>
#include <sys/queue.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/protosw.h>
#include <sys/errno.h>
#include <sys/stat.h>
#include <net/if.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/in_var.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>
#ifdef TCPDEBUG
#include <netinet/tcp_debug.h>
#endif
/*
* TCP protocol interface to socket abstraction.
*/
extern char *tcpstates[]; /* XXX ??? */
static int tcp_attach __P((struct socket *, struct proc *));
static int tcp_connect __P((struct tcpcb *, struct mbuf *,
struct proc *));
static struct tcpcb *
tcp_disconnect __P((struct tcpcb *));
static struct tcpcb *
tcp_usrclosed __P((struct tcpcb *));
#ifdef TCPDEBUG
#define TCPDEBUG0 int ostate
#define TCPDEBUG1() ostate = tp ? tp->t_state : 0
#define TCPDEBUG2(req) if (tp && (so->so_options & SO_DEBUG)) \
tcp_trace(TA_USER, ostate, tp, 0, req)
#else
#define TCPDEBUG0
#define TCPDEBUG1()
#define TCPDEBUG2(req)
#endif
/*
* TCP attaches to socket via pru_attach(), reserving space,
* and an internet control block.
*/
static int
tcp_usr_attach(struct socket *so, int proto, struct proc *p)
{
int s = splnet();
int error;
struct inpcb *inp = sotoinpcb(so);
struct tcpcb *tp = 0;
TCPDEBUG0;
TCPDEBUG1();
if (inp) {
error = EISCONN;
goto out;
}
error = tcp_attach(so, p);
if (error)
goto out;
if ((so->so_options & SO_LINGER) && so->so_linger == 0)
so->so_linger = TCP_LINGERTIME * hz;
tp = sototcpcb(so);
out:
TCPDEBUG2(PRU_ATTACH);
splx(s);
return error;
}
/*
* 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.
*/
static int
tcp_usr_detach(struct socket *so)
{
int s = splnet();
int error = 0;
struct inpcb *inp = sotoinpcb(so);
struct tcpcb *tp;
TCPDEBUG0;
if (inp == 0) {
splx(s);
return EINVAL; /* XXX */
}
tp = intotcpcb(inp);
TCPDEBUG1();
if (tp->t_state > TCPS_LISTEN)
tp = tcp_disconnect(tp);
else
tp = tcp_close(tp);
TCPDEBUG2(PRU_DETACH);
splx(s);
return error;
}
#define COMMON_START() TCPDEBUG0; \
do { \
if (inp == 0) { \
splx(s); \
return EINVAL; \
} \
tp = intotcpcb(inp); \
TCPDEBUG1(); \
} while(0)
#define COMMON_END(req) out: TCPDEBUG2(req); splx(s); return error; goto out
/*
* Give the socket an address.
*/
static int
tcp_usr_bind(struct socket *so, struct mbuf *nam, struct proc *p)
{
int s = splnet();
int error = 0;
struct inpcb *inp = sotoinpcb(so);
struct tcpcb *tp;
struct sockaddr_in *sinp;
COMMON_START();
/*
* Must check for multicast addresses and disallow binding
* to them.
*/
sinp = mtod(nam, struct sockaddr_in *);
if (sinp->sin_family == AF_INET &&
IN_MULTICAST(ntohl(sinp->sin_addr.s_addr))) {
error = EAFNOSUPPORT;
goto out;
}
error = in_pcbbind(inp, nam, p);
if (error)
goto out;
COMMON_END(PRU_BIND);
}
/*
* Prepare to accept connections.
*/
static int
tcp_usr_listen(struct socket *so, struct proc *p)
{
int s = splnet();
int error = 0;
struct inpcb *inp = sotoinpcb(so);
struct tcpcb *tp;
COMMON_START();
if (inp->inp_lport == 0)
error = in_pcbbind(inp, (struct mbuf *)0, p);
if (error == 0)
tp->t_state = TCPS_LISTEN;
COMMON_END(PRU_LISTEN);
}
/*
* 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.
*/
static int
tcp_usr_connect(struct socket *so, struct mbuf *nam, struct proc *p)
{
int s = splnet();
int error = 0;
struct inpcb *inp = sotoinpcb(so);
struct tcpcb *tp;
struct sockaddr_in *sinp;
COMMON_START();
/*
* Must disallow TCP ``connections'' to multicast addresses.
*/
sinp = mtod(nam, struct sockaddr_in *);
if (sinp->sin_family == AF_INET
&& IN_MULTICAST(ntohl(sinp->sin_addr.s_addr))) {
error = EAFNOSUPPORT;
goto out;
}
if ((error = tcp_connect(tp, nam, p)) != 0)
goto out;
error = tcp_output(tp);
COMMON_END(PRU_CONNECT);
}
/*
* 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.
*/
static int
tcp_usr_disconnect(struct socket *so)
{
int s = splnet();
int error = 0;
struct inpcb *inp = sotoinpcb(so);
struct tcpcb *tp;
COMMON_START();
tp = tcp_disconnect(tp);
COMMON_END(PRU_DISCONNECT);
}
/*
* Accept a connection. Essentially all the work is
* done at higher levels; just return the address
* of the peer, storing through addr.
*/
static int
tcp_usr_accept(struct socket *so, struct mbuf *nam)
{
int s = splnet();
int error = 0;
struct inpcb *inp = sotoinpcb(so);
struct tcpcb *tp;
COMMON_START();
in_setpeeraddr(so, nam);
COMMON_END(PRU_ACCEPT);
}
/*
* Mark the connection as being incapable of further output.
*/
static int
tcp_usr_shutdown(struct socket *so)
{
int s = splnet();
int error = 0;
struct inpcb *inp = sotoinpcb(so);
struct tcpcb *tp;
COMMON_START();
socantsendmore(so);
tp = tcp_usrclosed(tp);
if (tp)
error = tcp_output(tp);
COMMON_END(PRU_SHUTDOWN);
}
/*
* After a receive, possibly send window update to peer.
*/
static int
tcp_usr_rcvd(struct socket *so, int flags)
{
int s = splnet();
int error = 0;
struct inpcb *inp = sotoinpcb(so);
struct tcpcb *tp;
COMMON_START();
tcp_output(tp);
COMMON_END(PRU_RCVD);
}
/*
* Do a send by putting data in output queue and updating urgent
* marker if URG set. Possibly send more data.
*/
static int
tcp_usr_send(struct socket *so, int flags, struct mbuf *m, struct mbuf *nam,
struct mbuf *control, struct proc *p)
{
int s = splnet();
int error = 0;
struct inpcb *inp = sotoinpcb(so);
struct tcpcb *tp;
COMMON_START();
if (control && control->m_len) {
m_freem(control); /* XXX shouldn't caller do this??? */
if (m)
m_freem(m);
return EINVAL;
}
if(!(flags & PRUS_OOB)) {
sbappend(&so->so_snd, m);
if (nam && tp->t_state < TCPS_SYN_SENT) {
/*
* Do implied connect if not yet connected,
* initialize window to default value, and
* initialize maxseg/maxopd using peer's cached
* MSS.
*/
error = tcp_connect(tp, nam, p);
if (error)
goto out;
tp->snd_wnd = TTCP_CLIENT_SND_WND;
tcp_mss(tp, -1);
}
if (flags & PRUS_EOF) {
/*
* Close the send side of the connection after
* the data is sent.
*/
socantsendmore(so);
tp = tcp_usrclosed(tp);
}
if (tp != NULL)
error = tcp_output(tp);
} else {
if (sbspace(&so->so_snd) < -512) {
m_freem(m);
error = ENOBUFS;
goto out;
}
/*
* According to RFC961 (Assigned Protocols),
* the urgent pointer points to the last octet
* of urgent data. We continue, however,
* to consider it to indicate the first octet
* of data past the urgent section.
* Otherwise, snd_up should be one lower.
*/
sbappend(&so->so_snd, m);
if (nam && tp->t_state < TCPS_SYN_SENT) {
/*
* Do implied connect if not yet connected,
* initialize window to default value, and
* initialize maxseg/maxopd using peer's cached
* MSS.
*/
error = tcp_connect(tp, nam, p);
if (error)
goto out;
tp->snd_wnd = TTCP_CLIENT_SND_WND;
tcp_mss(tp, -1);
}
tp->snd_up = tp->snd_una + so->so_snd.sb_cc;
tp->t_force = 1;
error = tcp_output(tp);
tp->t_force = 0;
}
COMMON_END((flags & PRUS_OOB) ? PRU_SENDOOB :
((flags & PRUS_EOF) ? PRU_SEND_EOF : PRU_SEND));
}
/*
* Abort the TCP.
*/
static int
tcp_usr_abort(struct socket *so)
{
int s = splnet();
int error = 0;
struct inpcb *inp = sotoinpcb(so);
struct tcpcb *tp;
COMMON_START();
tp = tcp_drop(tp, ECONNABORTED);
COMMON_END(PRU_ABORT);
}
/*
* Receive out-of-band data.
*/
static int
tcp_usr_rcvoob(struct socket *so, struct mbuf *m, int flags)
{
int s = splnet();
int error = 0;
struct inpcb *inp = sotoinpcb(so);
struct tcpcb *tp;
COMMON_START();
if ((so->so_oobmark == 0 &&
(so->so_state & SS_RCVATMARK) == 0) ||
so->so_options & SO_OOBINLINE ||
tp->t_oobflags & TCPOOB_HADDATA) {
error = EINVAL;
goto out;
}
if ((tp->t_oobflags & TCPOOB_HAVEDATA) == 0) {
error = EWOULDBLOCK;
goto out;
}
m->m_len = 1;
*mtod(m, caddr_t) = tp->t_iobc;
if ((flags & MSG_PEEK) == 0)
tp->t_oobflags ^= (TCPOOB_HAVEDATA | TCPOOB_HADDATA);
COMMON_END(PRU_RCVOOB);
}
/* xxx - should be const */
struct pr_usrreqs tcp_usrreqs = {
tcp_usr_abort, tcp_usr_accept, tcp_usr_attach, tcp_usr_bind,
tcp_usr_connect, pru_connect2_notsupp, in_control, tcp_usr_detach,
tcp_usr_disconnect, tcp_usr_listen, in_setpeeraddr, tcp_usr_rcvd,
tcp_usr_rcvoob, tcp_usr_send, pru_sense_null, tcp_usr_shutdown,
in_setsockaddr, sosend, soreceive, soselect
};
/*
* Common subroutine to open a TCP connection to remote host specified
* by struct sockaddr_in in mbuf *nam. Call in_pcbbind to assign a local
* port number if needed. Call in_pcbladdr to do the routing and to choose
* a local host address (interface). If there is an existing incarnation
* of the same connection in TIME-WAIT state and if the remote host was
* sending CC options and if the connection duration was < MSL, then
* truncate the previous TIME-WAIT state and proceed.
* Initialize connection parameters and enter SYN-SENT state.
*/
static int
tcp_connect(tp, nam, p)
register struct tcpcb *tp;
struct mbuf *nam;
struct proc *p;
{
struct inpcb *inp = tp->t_inpcb, *oinp;
struct socket *so = inp->inp_socket;
struct tcpcb *otp;
struct sockaddr_in *sin = mtod(nam, struct sockaddr_in *);
struct sockaddr_in *ifaddr;
int error;
struct rmxp_tao *taop;
struct rmxp_tao tao_noncached;
if (inp->inp_lport == 0) {
error = in_pcbbind(inp, (struct mbuf *)0, p);
if (error)
return error;
}
/*
* Cannot simply call in_pcbconnect, because there might be an
* earlier incarnation of this same connection still in
* TIME_WAIT state, creating an ADDRINUSE error.
*/
error = in_pcbladdr(inp, nam, &ifaddr);
if (error)
return error;
oinp = in_pcblookuphash(inp->inp_pcbinfo,
sin->sin_addr, sin->sin_port,
inp->inp_laddr.s_addr != INADDR_ANY ? inp->inp_laddr
: ifaddr->sin_addr,
inp->inp_lport, 0);
if (oinp) {
if (oinp != inp && (otp = intotcpcb(oinp)) != NULL &&
otp->t_state == TCPS_TIME_WAIT &&
otp->t_duration < TCPTV_MSL &&
(otp->t_flags & TF_RCVD_CC))
otp = tcp_close(otp);
else
return EADDRINUSE;
}
if (inp->inp_laddr.s_addr == INADDR_ANY)
inp->inp_laddr = ifaddr->sin_addr;
inp->inp_faddr = sin->sin_addr;
inp->inp_fport = sin->sin_port;
in_pcbrehash(inp);
tp->t_template = tcp_template(tp);
if (tp->t_template == 0) {
in_pcbdisconnect(inp);
return ENOBUFS;
}
/* Compute window scaling to request. */
while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
(TCP_MAXWIN << tp->request_r_scale) < so->so_rcv.sb_hiwat)
tp->request_r_scale++;
soisconnecting(so);
tcpstat.tcps_connattempt++;
tp->t_state = TCPS_SYN_SENT;
tp->t_timer[TCPT_KEEP] = tcp_keepinit;
tp->iss = tcp_iss; tcp_iss += TCP_ISSINCR/2;
tcp_sendseqinit(tp);
/*
* Generate a CC value for this connection and
* check whether CC or CCnew should be used.
*/
if ((taop = tcp_gettaocache(tp->t_inpcb)) == NULL) {
taop = &tao_noncached;
bzero(taop, sizeof(*taop));
}
tp->cc_send = CC_INC(tcp_ccgen);
if (taop->tao_ccsent != 0 &&
CC_GEQ(tp->cc_send, taop->tao_ccsent)) {
taop->tao_ccsent = tp->cc_send;
} else {
taop->tao_ccsent = 0;
tp->t_flags |= TF_SENDCCNEW;
}
return 0;
}
int
tcp_ctloutput(op, so, level, optname, mp, p)
int op;
struct socket *so;
int level, optname;
struct mbuf **mp;
struct proc *p;
{
int error = 0, s;
struct inpcb *inp;
register struct tcpcb *tp;
register struct mbuf *m;
register int i;
s = splnet();
inp = sotoinpcb(so);
if (inp == NULL) {
splx(s);
if (op == PRCO_SETOPT && *mp)
(void) m_free(*mp);
return (ECONNRESET);
}
if (level != IPPROTO_TCP) {
error = ip_ctloutput(op, so, level, optname, mp, p);
splx(s);
return (error);
}
tp = intotcpcb(inp);
switch (op) {
case PRCO_SETOPT:
m = *mp;
switch (optname) {
case TCP_NODELAY:
if (m == NULL || m->m_len < sizeof (int))
error = EINVAL;
else if (*mtod(m, int *))
tp->t_flags |= TF_NODELAY;
else
tp->t_flags &= ~TF_NODELAY;
break;
case TCP_MAXSEG:
if (m && (i = *mtod(m, int *)) > 0 && i <= tp->t_maxseg)
tp->t_maxseg = i;
else
error = EINVAL;
break;
case TCP_NOOPT:
if (m == NULL || m->m_len < sizeof (int))
error = EINVAL;
else if (*mtod(m, int *))
tp->t_flags |= TF_NOOPT;
else
tp->t_flags &= ~TF_NOOPT;
break;
case TCP_NOPUSH:
if (m == NULL || m->m_len < sizeof (int))
error = EINVAL;
else if (*mtod(m, int *))
tp->t_flags |= TF_NOPUSH;
else
tp->t_flags &= ~TF_NOPUSH;
break;
default:
error = ENOPROTOOPT;
break;
}
if (m)
(void) m_free(m);
break;
case PRCO_GETOPT:
*mp = m = m_get(M_WAIT, MT_SOOPTS);
m->m_len = sizeof(int);
switch (optname) {
case TCP_NODELAY:
*mtod(m, int *) = tp->t_flags & TF_NODELAY;
break;
case TCP_MAXSEG:
*mtod(m, int *) = tp->t_maxseg;
break;
case TCP_NOOPT:
*mtod(m, int *) = tp->t_flags & TF_NOOPT;
break;
case TCP_NOPUSH:
*mtod(m, int *) = tp->t_flags & TF_NOPUSH;
break;
default:
error = ENOPROTOOPT;
break;
}
break;
}
splx(s);
return (error);
}
/*
* tcp_sendspace and tcp_recvspace are the default send and receive window
* sizes, respectively. These are obsolescent (this information should
* be set by the route).
*/
u_long tcp_sendspace = 1024*16;
SYSCTL_INT(_net_inet_tcp, TCPCTL_SENDSPACE, sendspace,
CTLFLAG_RW, &tcp_sendspace , 0, "");
u_long tcp_recvspace = 1024*16;
SYSCTL_INT(_net_inet_tcp, TCPCTL_RECVSPACE, recvspace,
CTLFLAG_RW, &tcp_recvspace , 0, "");
/*
* Attach TCP protocol to socket, allocating
* internet protocol control block, tcp control block,
* bufer space, and entering LISTEN state if to accept connections.
*/
static int
tcp_attach(so, p)
struct socket *so;
struct proc *p;
{
register struct tcpcb *tp;
struct inpcb *inp;
int error;
if (so->so_snd.sb_hiwat == 0 || so->so_rcv.sb_hiwat == 0) {
error = soreserve(so, tcp_sendspace, tcp_recvspace);
if (error)
return (error);
}
error = in_pcballoc(so, &tcbinfo, p);
if (error)
return (error);
inp = sotoinpcb(so);
tp = tcp_newtcpcb(inp);
if (tp == 0) {
int nofd = so->so_state & SS_NOFDREF; /* XXX */
so->so_state &= ~SS_NOFDREF; /* don't free the socket yet */
in_pcbdetach(inp);
so->so_state |= nofd;
return (ENOBUFS);
}
tp->t_state = TCPS_CLOSED;
return (0);
}
/*
* Initiate (or continue) disconnect.
* If embryonic state, just send reset (once).
* If in ``let data drain'' option and linger null, 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).
*/
static 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_options & SO_LINGER) && 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.
*/
static struct tcpcb *
tcp_usrclosed(tp)
register struct tcpcb *tp;
{
switch (tp->t_state) {
case TCPS_CLOSED:
case TCPS_LISTEN:
tp->t_state = TCPS_CLOSED;
tp = tcp_close(tp);
break;
case TCPS_SYN_SENT:
case TCPS_SYN_RECEIVED:
tp->t_flags |= TF_NEEDFIN;
break;
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);
/* To prevent the connection hanging in FIN_WAIT_2 forever. */
if (tp->t_state == TCPS_FIN_WAIT_2)
tp->t_timer[TCPT_2MSL] = tcp_maxidle;
}
return (tp);
}