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qemu/slirp/udp.c

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/*
* Copyright (c) 1982, 1986, 1988, 1990, 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. 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.
*
* @(#)udp_usrreq.c 8.4 (Berkeley) 1/21/94
* udp_usrreq.c,v 1.4 1994/10/02 17:48:45 phk Exp
*/
/*
* Changes and additions relating to SLiRP
* Copyright (c) 1995 Danny Gasparovski.
*
* Please read the file COPYRIGHT for the
* terms and conditions of the copyright.
*/
#include <slirp.h>
#include "ip_icmp.h"
#ifdef LOG_ENABLED
struct udpstat udpstat;
#endif
struct socket udb;
static u_int8_t udp_tos(struct socket *so);
static void udp_emu(struct socket *so, struct mbuf *m);
/*
* UDP protocol implementation.
* Per RFC 768, August, 1980.
*/
#ifndef COMPAT_42
#define UDPCKSUM 1
#else
#define UDPCKSUM 0 /* XXX */
#endif
struct socket *udp_last_so = &udb;
void
udp_init()
{
udb.so_next = udb.so_prev = &udb;
}
/* m->m_data points at ip packet header
* m->m_len length ip packet
* ip->ip_len length data (IPDU)
*/
void
udp_input(m, iphlen)
register struct mbuf *m;
int iphlen;
{
register struct ip *ip;
register struct udphdr *uh;
/* struct mbuf *opts = 0;*/
int len;
struct ip save_ip;
struct socket *so;
DEBUG_CALL("udp_input");
DEBUG_ARG("m = %lx", (long)m);
DEBUG_ARG("iphlen = %d", iphlen);
STAT(udpstat.udps_ipackets++);
/*
* Strip IP options, if any; should skip this,
* make available to user, and use on returned packets,
* but we don't yet have a way to check the checksum
* with options still present.
*/
if(iphlen > sizeof(struct ip)) {
ip_stripoptions(m, (struct mbuf *)0);
iphlen = sizeof(struct ip);
}
/*
* Get IP and UDP header together in first mbuf.
*/
ip = mtod(m, struct ip *);
uh = (struct udphdr *)((caddr_t)ip + iphlen);
/*
* Make mbuf data length reflect UDP length.
* If not enough data to reflect UDP length, drop.
*/
len = ntohs((u_int16_t)uh->uh_ulen);
if (ip->ip_len != len) {
if (len > ip->ip_len) {
STAT(udpstat.udps_badlen++);
goto bad;
}
m_adj(m, len - ip->ip_len);
ip->ip_len = len;
}
/*
* Save a copy of the IP header in case we want restore it
* for sending an ICMP error message in response.
*/
save_ip = *ip;
save_ip.ip_len+= iphlen; /* tcp_input subtracts this */
/*
* Checksum extended UDP header and data.
*/
if (UDPCKSUM && uh->uh_sum) {
memset(&((struct ipovly *)ip)->ih_mbuf, 0, sizeof(struct mbuf_ptr));
((struct ipovly *)ip)->ih_x1 = 0;
((struct ipovly *)ip)->ih_len = uh->uh_ulen;
/* keep uh_sum for ICMP reply
* uh->uh_sum = cksum(m, len + sizeof (struct ip));
* if (uh->uh_sum) {
*/
if(cksum(m, len + sizeof(struct ip))) {
STAT(udpstat.udps_badsum++);
goto bad;
}
}
/*
* handle DHCP/BOOTP
*/
if (ntohs(uh->uh_dport) == BOOTP_SERVER) {
bootp_input(m);
goto bad;
}
if (slirp_restrict)
goto bad;
/*
* handle TFTP
*/
if (ntohs(uh->uh_dport) == TFTP_SERVER) {
tftp_input(m);
goto bad;
}
/*
* Locate pcb for datagram.
*/
so = udp_last_so;
if (so->so_lport != uh->uh_sport ||
so->so_laddr.s_addr != ip->ip_src.s_addr) {
struct socket *tmp;
for (tmp = udb.so_next; tmp != &udb; tmp = tmp->so_next) {
if (tmp->so_lport == uh->uh_sport &&
tmp->so_laddr.s_addr == ip->ip_src.s_addr) {
tmp->so_faddr.s_addr = ip->ip_dst.s_addr;
tmp->so_fport = uh->uh_dport;
so = tmp;
break;
}
}
if (tmp == &udb) {
so = NULL;
} else {
STAT(udpstat.udpps_pcbcachemiss++);
udp_last_so = so;
}
}
if (so == NULL) {
/*
* If there's no socket for this packet,
* create one
*/
if ((so = socreate()) == NULL) goto bad;
if(udp_attach(so) == -1) {
DEBUG_MISC((dfd," udp_attach errno = %d-%s\n",
errno,strerror(errno)));
sofree(so);
goto bad;
}
/*
* Setup fields
*/
/* udp_last_so = so; */
so->so_laddr = ip->ip_src;
so->so_lport = uh->uh_sport;
if ((so->so_iptos = udp_tos(so)) == 0)
so->so_iptos = ip->ip_tos;
/*
* XXXXX Here, check if it's in udpexec_list,
* and if it is, do the fork_exec() etc.
*/
}
so->so_faddr = ip->ip_dst; /* XXX */
so->so_fport = uh->uh_dport; /* XXX */
iphlen += sizeof(struct udphdr);
m->m_len -= iphlen;
m->m_data += iphlen;
/*
* Now we sendto() the packet.
*/
if (so->so_emu)
udp_emu(so, m);
if(sosendto(so,m) == -1) {
m->m_len += iphlen;
m->m_data -= iphlen;
*ip=save_ip;
DEBUG_MISC((dfd,"udp tx errno = %d-%s\n",errno,strerror(errno)));
icmp_error(m, ICMP_UNREACH,ICMP_UNREACH_NET, 0,strerror(errno));
}
m_free(so->so_m); /* used for ICMP if error on sorecvfrom */
/* restore the orig mbuf packet */
m->m_len += iphlen;
m->m_data -= iphlen;
*ip=save_ip;
so->so_m=m; /* ICMP backup */
return;
bad:
m_freem(m);
/* if (opts) m_freem(opts); */
return;
}
int udp_output2(struct socket *so, struct mbuf *m,
struct sockaddr_in *saddr, struct sockaddr_in *daddr,
int iptos)
{
register struct udpiphdr *ui;
int error = 0;
DEBUG_CALL("udp_output");
DEBUG_ARG("so = %lx", (long)so);
DEBUG_ARG("m = %lx", (long)m);
DEBUG_ARG("saddr = %lx", (long)saddr->sin_addr.s_addr);
DEBUG_ARG("daddr = %lx", (long)daddr->sin_addr.s_addr);
/*
* Adjust for header
*/
m->m_data -= sizeof(struct udpiphdr);
m->m_len += sizeof(struct udpiphdr);
/*
* Fill in mbuf with extended UDP header
* and addresses and length put into network format.
*/
ui = mtod(m, struct udpiphdr *);
memset(&ui->ui_i.ih_mbuf, 0 , sizeof(struct mbuf_ptr));
ui->ui_x1 = 0;
ui->ui_pr = IPPROTO_UDP;
ui->ui_len = htons(m->m_len - sizeof(struct ip)); /* + sizeof (struct udphdr)); */
/* XXXXX Check for from-one-location sockets, or from-any-location sockets */
ui->ui_src = saddr->sin_addr;
ui->ui_dst = daddr->sin_addr;
ui->ui_sport = saddr->sin_port;
ui->ui_dport = daddr->sin_port;
ui->ui_ulen = ui->ui_len;
/*
* Stuff checksum and output datagram.
*/
ui->ui_sum = 0;
if (UDPCKSUM) {
if ((ui->ui_sum = cksum(m, /* sizeof (struct udpiphdr) + */ m->m_len)) == 0)
ui->ui_sum = 0xffff;
}
((struct ip *)ui)->ip_len = m->m_len;
((struct ip *)ui)->ip_ttl = IPDEFTTL;
((struct ip *)ui)->ip_tos = iptos;
STAT(udpstat.udps_opackets++);
error = ip_output(so, m);
return (error);
}
int udp_output(struct socket *so, struct mbuf *m,
struct sockaddr_in *addr)
{
struct sockaddr_in saddr, daddr;
saddr = *addr;
if ((so->so_faddr.s_addr & htonl(0xffffff00)) == special_addr.s_addr) {
if ((so->so_faddr.s_addr & htonl(0x000000ff)) == htonl(0xff))
saddr.sin_addr.s_addr = alias_addr.s_addr;
else if (addr->sin_addr.s_addr == loopback_addr.s_addr ||
(ntohl(so->so_faddr.s_addr) & 0xff) != CTL_ALIAS)
saddr.sin_addr.s_addr = so->so_faddr.s_addr;
}
daddr.sin_addr = so->so_laddr;
daddr.sin_port = so->so_lport;
return udp_output2(so, m, &saddr, &daddr, so->so_iptos);
}
int
udp_attach(so)
struct socket *so;
{
struct sockaddr_in addr;
if((so->s = socket(AF_INET,SOCK_DGRAM,0)) != -1) {
/*
* Here, we bind() the socket. Although not really needed
* (sendto() on an unbound socket will bind it), it's done
* here so that emulation of ytalk etc. don't have to do it
*/
addr.sin_family = AF_INET;
addr.sin_port = 0;
addr.sin_addr.s_addr = INADDR_ANY;
if(bind(so->s, (struct sockaddr *)&addr, sizeof(addr))<0) {
int lasterrno=errno;
closesocket(so->s);
so->s=-1;
#ifdef _WIN32
WSASetLastError(lasterrno);
#else
errno=lasterrno;
#endif
} else {
/* success, insert in queue */
so->so_expire = curtime + SO_EXPIRE;
insque(so,&udb);
}
}
return(so->s);
}
void
udp_detach(so)
struct socket *so;
{
closesocket(so->s);
/* if (so->so_m) m_free(so->so_m); done by sofree */
sofree(so);
}
static const struct tos_t udptos[] = {
{0, 53, IPTOS_LOWDELAY, 0}, /* DNS */
{517, 517, IPTOS_LOWDELAY, EMU_TALK}, /* talk */
{518, 518, IPTOS_LOWDELAY, EMU_NTALK}, /* ntalk */
{0, 7648, IPTOS_LOWDELAY, EMU_CUSEEME}, /* Cu-Seeme */
{0, 0, 0, 0}
};
static u_int8_t
udp_tos(struct socket *so)
{
int i = 0;
while(udptos[i].tos) {
if ((udptos[i].fport && ntohs(so->so_fport) == udptos[i].fport) ||
(udptos[i].lport && ntohs(so->so_lport) == udptos[i].lport)) {
so->so_emu = udptos[i].emu;
return udptos[i].tos;
}
i++;
}
return 0;
}
#ifdef EMULATE_TALK
#include "talkd.h"
#endif
/*
* Here, talk/ytalk/ntalk requests must be emulated
*/
static void
udp_emu(struct socket *so, struct mbuf *m)
{
struct sockaddr_in addr;
socklen_t addrlen = sizeof(addr);
#ifdef EMULATE_TALK
CTL_MSG_OLD *omsg;
CTL_MSG *nmsg;
char buff[sizeof(CTL_MSG)];
u_char type;
struct talk_request {
struct talk_request *next;
struct socket *udp_so;
struct socket *tcp_so;
} *req;
static struct talk_request *req_tbl = 0;
#endif
struct cu_header {
uint16_t d_family; // destination family
uint16_t d_port; // destination port
uint32_t d_addr; // destination address
uint16_t s_family; // source family
uint16_t s_port; // source port
uint32_t so_addr; // source address
uint32_t seqn; // sequence number
uint16_t message; // message
uint16_t data_type; // data type
uint16_t pkt_len; // packet length
} *cu_head;
switch(so->so_emu) {
#ifdef EMULATE_TALK
case EMU_TALK:
case EMU_NTALK:
/*
* Talk emulation. We always change the ctl_addr to get
* some answers from the daemon. When an ANNOUNCE comes,
* we send LEAVE_INVITE to the local daemons. Also when a
* DELETE comes, we send copies to the local daemons.
*/
if (getsockname(so->s, (struct sockaddr *)&addr, &addrlen) < 0)
return;
#define IS_OLD (so->so_emu == EMU_TALK)
#define COPY_MSG(dest, src) { dest->type = src->type; \
dest->id_num = src->id_num; \
dest->pid = src->pid; \
dest->addr = src->addr; \
dest->ctl_addr = src->ctl_addr; \
memcpy(&dest->l_name, &src->l_name, NAME_SIZE_OLD); \
memcpy(&dest->r_name, &src->r_name, NAME_SIZE_OLD); \
memcpy(&dest->r_tty, &src->r_tty, TTY_SIZE); }
#define OTOSIN(ptr, field) ((struct sockaddr_in *)&ptr->field)
/* old_sockaddr to sockaddr_in */
if (IS_OLD) { /* old talk */
omsg = mtod(m, CTL_MSG_OLD*);
nmsg = (CTL_MSG *) buff;
type = omsg->type;
OTOSIN(omsg, ctl_addr)->sin_port = addr.sin_port;
OTOSIN(omsg, ctl_addr)->sin_addr = our_addr;
pstrcpy(omsg->l_name, NAME_SIZE_OLD, getlogin());
} else { /* new talk */
omsg = (CTL_MSG_OLD *) buff;
nmsg = mtod(m, CTL_MSG *);
type = nmsg->type;
OTOSIN(nmsg, ctl_addr)->sin_port = addr.sin_port;
OTOSIN(nmsg, ctl_addr)->sin_addr = our_addr;
pstrcpy(nmsg->l_name, NAME_SIZE_OLD, getlogin());
}
if (type == LOOK_UP)
return; /* for LOOK_UP this is enough */
if (IS_OLD) { /* make a copy of the message */
COPY_MSG(nmsg, omsg);
nmsg->vers = 1;
nmsg->answer = 0;
} else
COPY_MSG(omsg, nmsg);
/*
* If if is an ANNOUNCE message, we go through the
* request table to see if a tcp port has already
* been redirected for this socket. If not, we solisten()
* a new socket and add this entry to the table.
* The port number of the tcp socket and our IP
* are put to the addr field of the message structures.
* Then a LEAVE_INVITE is sent to both local daemon
* ports, 517 and 518. This is why we have two copies
* of the message, one in old talk and one in new talk
* format.
*/
if (type == ANNOUNCE) {
int s;
u_short temp_port;
for(req = req_tbl; req; req = req->next)
if (so == req->udp_so)
break; /* found it */
if (!req) { /* no entry for so, create new */
req = (struct talk_request *)
malloc(sizeof(struct talk_request));
req->udp_so = so;
req->tcp_so = solisten(0,
OTOSIN(omsg, addr)->sin_addr.s_addr,
OTOSIN(omsg, addr)->sin_port,
SS_FACCEPTONCE);
req->next = req_tbl;
req_tbl = req;
}
/* replace port number in addr field */
addrlen = sizeof(addr);
getsockname(req->tcp_so->s,
(struct sockaddr *) &addr,
&addrlen);
OTOSIN(omsg, addr)->sin_port = addr.sin_port;
OTOSIN(omsg, addr)->sin_addr = our_addr;
OTOSIN(nmsg, addr)->sin_port = addr.sin_port;
OTOSIN(nmsg, addr)->sin_addr = our_addr;
/* send LEAVE_INVITEs */
temp_port = OTOSIN(omsg, ctl_addr)->sin_port;
OTOSIN(omsg, ctl_addr)->sin_port = 0;
OTOSIN(nmsg, ctl_addr)->sin_port = 0;
omsg->type = nmsg->type = LEAVE_INVITE;
s = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
addr.sin_addr = our_addr;
addr.sin_family = AF_INET;
addr.sin_port = htons(517);
sendto(s, (char *)omsg, sizeof(*omsg), 0,
(struct sockaddr *)&addr, sizeof(addr));
addr.sin_port = htons(518);
sendto(s, (char *)nmsg, sizeof(*nmsg), 0,
(struct sockaddr *) &addr, sizeof(addr));
closesocket(s) ;
omsg->type = nmsg->type = ANNOUNCE;
OTOSIN(omsg, ctl_addr)->sin_port = temp_port;
OTOSIN(nmsg, ctl_addr)->sin_port = temp_port;
}
/*
* If it is a DELETE message, we send a copy to the
* local daemons. Then we delete the entry corresponding
* to our socket from the request table.
*/
if (type == DELETE) {
struct talk_request *temp_req, *req_next;
int s;
u_short temp_port;
temp_port = OTOSIN(omsg, ctl_addr)->sin_port;
OTOSIN(omsg, ctl_addr)->sin_port = 0;
OTOSIN(nmsg, ctl_addr)->sin_port = 0;
s = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
addr.sin_addr = our_addr;
addr.sin_family = AF_INET;
addr.sin_port = htons(517);
sendto(s, (char *)omsg, sizeof(*omsg), 0,
(struct sockaddr *)&addr, sizeof(addr));
addr.sin_port = htons(518);
sendto(s, (char *)nmsg, sizeof(*nmsg), 0,
(struct sockaddr *)&addr, sizeof(addr));
closesocket(s);
OTOSIN(omsg, ctl_addr)->sin_port = temp_port;
OTOSIN(nmsg, ctl_addr)->sin_port = temp_port;
/* delete table entry */
if (so == req_tbl->udp_so) {
temp_req = req_tbl;
req_tbl = req_tbl->next;
free(temp_req);
} else {
temp_req = req_tbl;
for(req = req_tbl->next; req; req = req_next) {
req_next = req->next;
if (so == req->udp_so) {
temp_req->next = req_next;
free(req);
break;
} else {
temp_req = req;
}
}
}
}
return;
#endif
case EMU_CUSEEME:
/*
* Cu-SeeMe emulation.
* Hopefully the packet is more that 16 bytes long. We don't
* do any other tests, just replace the address and port
* fields.
*/
if (m->m_len >= sizeof (*cu_head)) {
if (getsockname(so->s, (struct sockaddr *)&addr, &addrlen) < 0)
return;
cu_head = mtod(m, struct cu_header *);
cu_head->s_port = addr.sin_port;
cu_head->so_addr = our_addr.s_addr;
}
return;
}
}
struct socket *
udp_listen(port, laddr, lport, flags)
u_int port;
u_int32_t laddr;
u_int lport;
int flags;
{
struct sockaddr_in addr;
struct socket *so;
socklen_t addrlen = sizeof(struct sockaddr_in), opt = 1;
if ((so = socreate()) == NULL) {
free(so);
return NULL;
}
so->s = socket(AF_INET,SOCK_DGRAM,0);
so->so_expire = curtime + SO_EXPIRE;
insque(so,&udb);
addr.sin_family = AF_INET;
addr.sin_addr.s_addr = INADDR_ANY;
addr.sin_port = port;
if (bind(so->s,(struct sockaddr *)&addr, addrlen) < 0) {
udp_detach(so);
return NULL;
}
setsockopt(so->s,SOL_SOCKET,SO_REUSEADDR,(char *)&opt,sizeof(int));
/* setsockopt(so->s,SOL_SOCKET,SO_OOBINLINE,(char *)&opt,sizeof(int)); */
getsockname(so->s,(struct sockaddr *)&addr,&addrlen);
so->so_fport = addr.sin_port;
if (addr.sin_addr.s_addr == 0 || addr.sin_addr.s_addr == loopback_addr.s_addr)
so->so_faddr = alias_addr;
else
so->so_faddr = addr.sin_addr;
so->so_lport = lport;
so->so_laddr.s_addr = laddr;
if (flags != SS_FACCEPTONCE)
so->so_expire = 0;
so->so_state = SS_ISFCONNECTED;
return so;
}
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