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qemu/slirp/misc.c
Jan Kiszka e6d43cfb1f slirp: Forward ICMP echo requests via unprivileged sockets 
Linux 3.0 gained support for unprivileged ICMP ping sockets. Use this
feature to forward guest pings to the outer world. The host admin has to
set the ping_group_range in order to grant access to those sockets. To
allow ping for the users group (GID 100):

echo 100 100 > /proc/sys/net/ipv4/ping_group_range

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2011-07-23 10:19:50 -05:00

424 lines
10 KiB
C
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/*
* Copyright (c) 1995 Danny Gasparovski.
*
* Please read the file COPYRIGHT for the
* terms and conditions of the copyright.
*/
#include <slirp.h>
#include <libslirp.h>
#include "monitor.h"
#ifdef DEBUG
int slirp_debug = DBG_CALL|DBG_MISC|DBG_ERROR;
#endif
struct quehead {
struct quehead *qh_link;
struct quehead *qh_rlink;
};
inline void
insque(void *a, void *b)
{
register struct quehead *element = (struct quehead *) a;
register struct quehead *head = (struct quehead *) b;
element->qh_link = head->qh_link;
head->qh_link = (struct quehead *)element;
element->qh_rlink = (struct quehead *)head;
((struct quehead *)(element->qh_link))->qh_rlink
= (struct quehead *)element;
}
inline void
remque(void *a)
{
register struct quehead *element = (struct quehead *) a;
((struct quehead *)(element->qh_link))->qh_rlink = element->qh_rlink;
((struct quehead *)(element->qh_rlink))->qh_link = element->qh_link;
element->qh_rlink = NULL;
}
int add_exec(struct ex_list **ex_ptr, int do_pty, char *exec,
struct in_addr addr, int port)
{
struct ex_list *tmp_ptr;
/* First, check if the port is "bound" */
for (tmp_ptr = *ex_ptr; tmp_ptr; tmp_ptr = tmp_ptr->ex_next) {
if (port == tmp_ptr->ex_fport &&
addr.s_addr == tmp_ptr->ex_addr.s_addr)
return -1;
}
tmp_ptr = *ex_ptr;
*ex_ptr = (struct ex_list *)malloc(sizeof(struct ex_list));
(*ex_ptr)->ex_fport = port;
(*ex_ptr)->ex_addr = addr;
(*ex_ptr)->ex_pty = do_pty;
(*ex_ptr)->ex_exec = (do_pty == 3) ? exec : strdup(exec);
(*ex_ptr)->ex_next = tmp_ptr;
return 0;
}
#ifndef HAVE_STRERROR
/*
* For systems with no strerror
*/
extern int sys_nerr;
extern char *sys_errlist[];
char *
strerror(error)
int error;
{
if (error < sys_nerr)
return sys_errlist[error];
else
return "Unknown error.";
}
#endif
#ifdef _WIN32
int
fork_exec(struct socket *so, const char *ex, int do_pty)
{
/* not implemented */
return 0;
}
#else
/*
* XXX This is ugly
* We create and bind a socket, then fork off to another
* process, which connects to this socket, after which we
* exec the wanted program. If something (strange) happens,
* the accept() call could block us forever.
*
* do_pty = 0 Fork/exec inetd style
* do_pty = 1 Fork/exec using slirp.telnetd
* do_ptr = 2 Fork/exec using pty
*/
int
fork_exec(struct socket *so, const char *ex, int do_pty)
{
int s;
struct sockaddr_in addr;
socklen_t addrlen = sizeof(addr);
int opt;
int master = -1;
const char *argv[256];
/* don't want to clobber the original */
char *bptr;
const char *curarg;
int c, i, ret;
pid_t pid;
DEBUG_CALL("fork_exec");
DEBUG_ARG("so = %lx", (long)so);
DEBUG_ARG("ex = %lx", (long)ex);
DEBUG_ARG("do_pty = %lx", (long)do_pty);
if (do_pty == 2) {
return 0;
} else {
addr.sin_family = AF_INET;
addr.sin_port = 0;
addr.sin_addr.s_addr = INADDR_ANY;
if ((s = qemu_socket(AF_INET, SOCK_STREAM, 0)) < 0 ||
bind(s, (struct sockaddr *)&addr, addrlen) < 0 ||
listen(s, 1) < 0) {
lprint("Error: inet socket: %s\n", strerror(errno));
closesocket(s);
return 0;
}
}
pid = fork();
switch(pid) {
case -1:
lprint("Error: fork failed: %s\n", strerror(errno));
close(s);
if (do_pty == 2)
close(master);
return 0;
case 0:
setsid();
/* Set the DISPLAY */
if (do_pty == 2) {
(void) close(master);
#ifdef TIOCSCTTY /* XXXXX */
ioctl(s, TIOCSCTTY, (char *)NULL);
#endif
} else {
getsockname(s, (struct sockaddr *)&addr, &addrlen);
close(s);
/*
* Connect to the socket
* XXX If any of these fail, we're in trouble!
*/
s = qemu_socket(AF_INET, SOCK_STREAM, 0);
addr.sin_addr = loopback_addr;
do {
ret = connect(s, (struct sockaddr *)&addr, addrlen);
} while (ret < 0 && errno == EINTR);
}
dup2(s, 0);
dup2(s, 1);
dup2(s, 2);
for (s = getdtablesize() - 1; s >= 3; s--)
close(s);
i = 0;
bptr = qemu_strdup(ex); /* No need to free() this */
if (do_pty == 1) {
/* Setup "slirp.telnetd -x" */
argv[i++] = "slirp.telnetd";
argv[i++] = "-x";
argv[i++] = bptr;
} else
do {
/* Change the string into argv[] */
curarg = bptr;
while (*bptr != ' ' && *bptr != (char)0)
bptr++;
c = *bptr;
*bptr++ = (char)0;
argv[i++] = strdup(curarg);
} while (c);
argv[i] = NULL;
execvp(argv[0], (char **)argv);
/* Ooops, failed, let's tell the user why */
fprintf(stderr, "Error: execvp of %s failed: %s\n",
argv[0], strerror(errno));
close(0); close(1); close(2); /* XXX */
exit(1);
default:
qemu_add_child_watch(pid);
if (do_pty == 2) {
close(s);
so->s = master;
} else {
/*
* XXX this could block us...
* XXX Should set a timer here, and if accept() doesn't
* return after X seconds, declare it a failure
* The only reason this will block forever is if socket()
* of connect() fail in the child process
*/
do {
so->s = accept(s, (struct sockaddr *)&addr, &addrlen);
} while (so->s < 0 && errno == EINTR);
closesocket(s);
opt = 1;
setsockopt(so->s,SOL_SOCKET,SO_REUSEADDR,(char *)&opt,sizeof(int));
opt = 1;
setsockopt(so->s,SOL_SOCKET,SO_OOBINLINE,(char *)&opt,sizeof(int));
}
fd_nonblock(so->s);
/* Append the telnet options now */
if (so->so_m != NULL && do_pty == 1) {
sbappend(so, so->so_m);
so->so_m = NULL;
}
return 1;
}
}
#endif
#ifndef HAVE_STRDUP
char *
strdup(str)
const char *str;
{
char *bptr;
bptr = (char *)malloc(strlen(str)+1);
strcpy(bptr, str);
return bptr;
}
#endif
#include "monitor.h"
void lprint(const char *format, ...)
{
va_list args;
va_start(args, format);
monitor_vprintf(default_mon, format, args);
va_end(args);
}
void
u_sleep(int usec)
{
struct timeval t;
fd_set fdset;
FD_ZERO(&fdset);
t.tv_sec = 0;
t.tv_usec = usec * 1000;
select(0, &fdset, &fdset, &fdset, &t);
}
/*
* Set fd blocking and non-blocking
*/
void
fd_nonblock(int fd)
{
#ifdef FIONBIO
#ifdef _WIN32
unsigned long opt = 1;
#else
int opt = 1;
#endif
ioctlsocket(fd, FIONBIO, &opt);
#else
int opt;
opt = fcntl(fd, F_GETFL, 0);
opt |= O_NONBLOCK;
fcntl(fd, F_SETFL, opt);
#endif
}
void
fd_block(int fd)
{
#ifdef FIONBIO
#ifdef _WIN32
unsigned long opt = 0;
#else
int opt = 0;
#endif
ioctlsocket(fd, FIONBIO, &opt);
#else
int opt;
opt = fcntl(fd, F_GETFL, 0);
opt &= ~O_NONBLOCK;
fcntl(fd, F_SETFL, opt);
#endif
}
void slirp_connection_info(Slirp *slirp, Monitor *mon)
{
const char * const tcpstates[] = {
[TCPS_CLOSED] = "CLOSED",
[TCPS_LISTEN] = "LISTEN",
[TCPS_SYN_SENT] = "SYN_SENT",
[TCPS_SYN_RECEIVED] = "SYN_RCVD",
[TCPS_ESTABLISHED] = "ESTABLISHED",
[TCPS_CLOSE_WAIT] = "CLOSE_WAIT",
[TCPS_FIN_WAIT_1] = "FIN_WAIT_1",
[TCPS_CLOSING] = "CLOSING",
[TCPS_LAST_ACK] = "LAST_ACK",
[TCPS_FIN_WAIT_2] = "FIN_WAIT_2",
[TCPS_TIME_WAIT] = "TIME_WAIT",
};
struct in_addr dst_addr;
struct sockaddr_in src;
socklen_t src_len;
uint16_t dst_port;
struct socket *so;
const char *state;
char buf[20];
int n;
monitor_printf(mon, " Protocol[State] FD Source Address Port "
"Dest. Address Port RecvQ SendQ\n");
for (so = slirp->tcb.so_next; so != &slirp->tcb; so = so->so_next) {
if (so->so_state & SS_HOSTFWD) {
state = "HOST_FORWARD";
} else if (so->so_tcpcb) {
state = tcpstates[so->so_tcpcb->t_state];
} else {
state = "NONE";
}
if (so->so_state & (SS_HOSTFWD | SS_INCOMING)) {
src_len = sizeof(src);
getsockname(so->s, (struct sockaddr *)&src, &src_len);
dst_addr = so->so_laddr;
dst_port = so->so_lport;
} else {
src.sin_addr = so->so_laddr;
src.sin_port = so->so_lport;
dst_addr = so->so_faddr;
dst_port = so->so_fport;
}
n = snprintf(buf, sizeof(buf), " TCP[%s]", state);
memset(&buf[n], ' ', 19 - n);
buf[19] = 0;
monitor_printf(mon, "%s %3d %15s %5d ", buf, so->s,
src.sin_addr.s_addr ? inet_ntoa(src.sin_addr) : "*",
ntohs(src.sin_port));
monitor_printf(mon, "%15s %5d %5d %5d\n",
inet_ntoa(dst_addr), ntohs(dst_port),
so->so_rcv.sb_cc, so->so_snd.sb_cc);
}
for (so = slirp->udb.so_next; so != &slirp->udb; so = so->so_next) {
if (so->so_state & SS_HOSTFWD) {
n = snprintf(buf, sizeof(buf), " UDP[HOST_FORWARD]");
src_len = sizeof(src);
getsockname(so->s, (struct sockaddr *)&src, &src_len);
dst_addr = so->so_laddr;
dst_port = so->so_lport;
} else {
n = snprintf(buf, sizeof(buf), " UDP[%d sec]",
(so->so_expire - curtime) / 1000);
src.sin_addr = so->so_laddr;
src.sin_port = so->so_lport;
dst_addr = so->so_faddr;
dst_port = so->so_fport;
}
memset(&buf[n], ' ', 19 - n);
buf[19] = 0;
monitor_printf(mon, "%s %3d %15s %5d ", buf, so->s,
src.sin_addr.s_addr ? inet_ntoa(src.sin_addr) : "*",
ntohs(src.sin_port));
monitor_printf(mon, "%15s %5d %5d %5d\n",
inet_ntoa(dst_addr), ntohs(dst_port),
so->so_rcv.sb_cc, so->so_snd.sb_cc);
}
for (so = slirp->icmp.so_next; so != &slirp->icmp; so = so->so_next) {
n = snprintf(buf, sizeof(buf), " ICMP[%d sec]",
(so->so_expire - curtime) / 1000);
src.sin_addr = so->so_laddr;
dst_addr = so->so_faddr;
memset(&buf[n], ' ', 19 - n);
buf[19] = 0;
monitor_printf(mon, "%s %3d %15s - ", buf, so->s,
src.sin_addr.s_addr ? inet_ntoa(src.sin_addr) : "*");
monitor_printf(mon, "%15s - %5d %5d\n", inet_ntoa(dst_addr),
so->so_rcv.sb_cc, so->so_snd.sb_cc);
}
}
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