pppoe.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
* pppoe.c - pppd plugin to handle PPPoE operation.
*
* Copyright 2004 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#include <unistd.h>
#include <stddef.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <fcntl.h>
#include <strings.h>
#include <sys/stropts.h>
#include <netinet/in.h>
#include <net/pppio.h>
#include <net/sppptun.h>
#include <net/pppoe.h>
#include "pppd.h"
#include "pathnames.h"
#pragma ident "%Z%%M% %I% %E% SMI"
/* Saved hook pointers */
static int (*old_check_options)(uid_t uid);
static int (*old_updown_script)(const char ***argsp);
static int (*old_sys_read_packet)(int retv, struct strbuf *ctrl,
struct strbuf *data, int flags);
/* Room for 3 IPv4 addresses and metric */
#define RTE_MSG_LEN (3*16 + 10 + 1)
/* Environment string for routes */
#define RTE_STR "ROUTE_%d"
/*
* strioctl()
*
* wrapper for STREAMS I_STR ioctl.
*/
static int
strioctl(int fd, int cmd, void *ptr, int ilen, int olen)
{
struct strioctl str;
str.ic_cmd = cmd;
str.ic_timout = 0; /* Use default timer; 15 seconds */
str.ic_len = ilen;
str.ic_dp = ptr;
if (ioctl(fd, I_STR, &str) == -1) {
return (-1);
}
if (str.ic_len != olen) {
return (-1);
}
return (0);
}
/*
* If the user named the tunneling device, check that it is
* reasonable; otherwise check that standard input is the tunnel.
*/
static int
pppoe_check_options(uid_t uid)
{
int tstfd; /* fd for device being checked */
int err; /* saved errno value */
int retv; /* return value */
int intv; /* integer return value (from ioctl) */
union ppptun_name ptn;
if (devnam[0] != '\0') {
/*
* Open as real user so that modes on device can be
* used to limit access.
*/
if (!devnam_info.priv)
(void) seteuid(uid);
tstfd = open(devnam, O_NONBLOCK | O_RDWR, 0);
err = errno;
if (!devnam_info.priv)
(void) seteuid(0);
if (tstfd == -1) {
errno = err;
option_error("unable to open %s: %m", devnam);
return (-1);
}
retv = strioctl(tstfd, PPPTUN_GDATA, &ptn, 0, sizeof (ptn));
(void) close(tstfd);
if (retv == -1) {
option_error("device %s is not a PPP tunneling device",
devnam);
return (-1);
}
} else {
retv = strioctl(0, PPPIO_GTYPE, &intv, 0, sizeof (intv));
if (retv == -1) {
option_error("standard input is not a PPP device");
return (-1);
}
retv = strioctl(0, PPPTUN_GDATA, &ptn, 0, sizeof (ptn));
if (retv == -1) {
option_error("standard input is not a PPP tunnel");
return (-1);
}
if (strcmp(ptn.ptn_name + strlen(ptn.ptn_name) - 6,
":pppoe") != 0) {
option_error("standard input not connected to PPPoE");
return (-1);
}
}
if (old_check_options != NULL &&
old_check_options != pppoe_check_options)
return ((*old_check_options)(uid));
return (0);
}
/*
* When we're about to call one of the up or down scripts, change the
* second argument to contain the interface name and selected PPPoE
* service.
*/
static int
pppoe_updown_script(const char ***argsp)
{
const char *cp;
if ((*argsp)[2] == devnam &&
(cp = script_getenv("IF_AND_SERVICE")) != NULL)
(*argsp)[2] = cp;
if (old_updown_script != NULL &&
old_updown_script != pppoe_updown_script)
return ((*old_updown_script)(argsp));
return (0);
}
/*
* Concatenate and save strings from command line into environment
* variable.
*/
static void
cat_save_env(char **argv, char idchar, const char *envname)
{
char **argp;
int totlen;
char *str;
char *cp;
totlen = 0;
for (argp = argv; argp[0] != NULL; argp += 2)
if (*argp[0] == idchar)
totlen += strlen(argp[1]) + 1;
if ((str = malloc(totlen + 1)) == NULL) {
error("cannot malloc PPPoE environment for %s", envname);
return;
}
cp = str;
for (argp = argv; argp[0] != NULL; argp += 2)
if (*argp[0] == idchar) {
(void) strcpy(cp, argp[1]);
cp += strlen(cp);
*cp++ = '\n';
}
*cp = '\0';
script_setenv(envname, str, 0);
}
/*
* Convert Message Of The Moment (MOTM) and Host Uniform Resource
* Locator (HURL) strings into environment variables and command-line
* arguments for script.
*/
static void
handle_motm_hurl(char **argv, int argc, const uint8_t *tagp, int pktlen)
{
int ttype;
int tlen;
char *str;
char **oargv = argv;
/* Must have room for two strings and NULL terminator. */
while (argc >= 3) {
str = NULL;
while (pktlen >= POET_HDRLEN) {
ttype = POET_GET_TYPE(tagp);
if (ttype == POETT_END)
break;
tlen = POET_GET_LENG(tagp);
if (tlen > pktlen - POET_HDRLEN)
break;
if (ttype == POETT_HURL || ttype == POETT_MOTM) {
if ((str = malloc(tlen + 1)) == NULL) {
error("cannot malloc PPPoE message");
break;
}
(void) memcpy(str, POET_DATA(tagp), tlen);
str[tlen] = '\0';
}
pktlen -= POET_HDRLEN + tlen;
tagp += POET_HDRLEN + tlen;
if (str != NULL)
break;
}
if (str == NULL)
break;
*argv++ = ttype == POETT_HURL ? "hurl" : "motm";
*argv++ = str;
argc -= 2;
}
*argv = NULL;
cat_save_env(oargv, 'h', "HURL");
cat_save_env(oargv, 'm', "MOTM");
}
/*
* Convert IP Route Add structures into environment variables and
* command-line arguments for script.
*/
static void
handle_ip_route_add(char **argv, int argc, const uint8_t *tagp, int pktlen)
{
int ttype;
int tlen;
char *str;
poer_t poer;
int idx;
char envname[sizeof (RTE_STR) + 10];
idx = 0;
/* Must have room for four strings and NULL terminator. */
while (argc >= 5) {
str = NULL;
while (pktlen >= POET_HDRLEN) {
ttype = POET_GET_TYPE(tagp);
if (ttype == POETT_END)
break;
tlen = POET_GET_LENG(tagp);
if (tlen > pktlen - POET_HDRLEN)
break;
if (ttype == POETT_RTEADD && tlen >= sizeof (poer) &&
(str = malloc(RTE_MSG_LEN)) == NULL) {
error("cannot malloc PPPoE route");
break;
}
pktlen -= POET_HDRLEN + tlen;
tagp += POET_HDRLEN + tlen;
if (str != NULL)
break;
}
if (str == NULL)
break;
/* No alignment restrictions on source; copy to local. */
(void) memcpy(&poer, POET_DATA(tagp), sizeof (poer));
(void) slprintf(str, RTE_MSG_LEN, "%I %I %I %d",
poer.poer_dest_network, poer.poer_subnet_mask,
poer.poer_gateway, (int)poer.poer_metric);
/* Save off the environment variable version of this. */
(void) slprintf(envname, sizeof (envname), RTE_STR, ++idx);
script_setenv(envname, str, 0);
*argv++ = str; /* Destination */
str = strchr(str, ' ');
*str++ = '\0';
*argv++ = str; /* Subnet mask */
str = strchr(str, ' ');
*str++ = '\0';
*argv++ = str; /* Gateway */
str = strchr(str, ' ');
*str++ = '\0';
*argv++ = str; /* Metric */
argc -= 4;
}
*argv = NULL;
}
/*
* If we get here, then the driver has already validated the sender,
* the PPPoE version, the message length, and session ID. The code
* number is known not to be zero.
*/
static int
handle_pppoe_input(const ppptun_atype *pma, struct strbuf *ctrl,
struct strbuf *data)
{
const poep_t *poep;
struct ppp_ls *plp;
const char *mname;
const char *cstr;
char *str;
char *cp;
char *argv[64];
pid_t rpid;
char **argp;
int idx;
char envname[sizeof (RTE_STR) + 10];
const uint8_t *tagp;
int pktlen;
/*
* Warning: the data->buf pointer here is not necessarily properly
* aligned for access to the poep_session_id or poep_length members.
*/
/* LINTED: alignment */
poep = (const poep_t *)data->buf;
tagp = (const uint8_t *)poep + offsetof(poep_t, poep_length);
pktlen = (tagp[0] << 8) + tagp[1];
tagp = (const uint8_t *)(poep + 1);
switch (poep->poep_code) {
case POECODE_PADT:
dbglog("received PPPoE PADT; connection has been closed");
/* LINTED: alignment */
plp = (struct ppp_ls *)ctrl->buf;
plp->magic = PPPLSMAGIC;
plp->ppp_message = PPP_LINKSTAT_HANGUP;
ctrl->len = sizeof (*plp);
return (0);
/* Active Discovery Message and Network extensions */
case POECODE_PADM:
case POECODE_PADN:
if (poep->poep_code == POECODE_PADM) {
argv[0] = _ROOT_PATH "/etc/ppp/pppoe-msg";
mname = "PADM";
handle_motm_hurl(argv + 4, Dim(argv) - 4, tagp, pktlen);
} else {
argv[0] = _ROOT_PATH "/etc/ppp/pppoe-network";
mname = "PADN";
handle_ip_route_add(argv + 4, Dim(argv) - 4, tagp,
pktlen);
}
argv[1] = ifname;
/* Note: strdup doesn't handle NULL input. */
str = NULL;
if ((cstr = script_getenv("IF_AND_SERVICE")) == NULL ||
(str = strdup(cstr)) == NULL) {
argv[2] = argv[3] = "";
} else {
if ((cp = strrchr(str, ':')) == NULL)
cp = str + strlen(str);
else
*cp++ = '\0';
argv[2] = str;
argv[3] = cp;
}
rpid = run_program(argv[0], argv, 0, NULL, NULL);
if (rpid == (pid_t)0)
dbglog("ignored PPPoE %s; no %s script", mname,
argv[0]);
else if (rpid != (pid_t)-1)
dbglog("PPPoE %s: started PID %d", mname, rpid);
if (str != NULL)
free(str);
/* Free storage allocated by handle_{motm_hurl,ip_route_add} */
idx = 0;
for (argp = argv + 4; *argp != NULL; ) {
if (poep->poep_code == POECODE_PADM) {
free(argp[1]);
argp += 2;
} else {
free(argp[0]);
argp += 4;
(void) slprintf(envname, sizeof (envname),
RTE_STR, ++idx);
script_unsetenv(envname);
}
}
if (poep->poep_code == POECODE_PADM) {
script_unsetenv("HURL");
script_unsetenv("MOTM");
}
break;
default:
warn("unexpected PPPoE code %d from %s", poep->poep_code,
ether_ntoa(&pma->pta_pppoe.ptma_mac_ether_addr));
break;
}
return (-1);
}
/*
* sys-solaris has just read in a packet; grovel through it and see if
* it's something we need to handle ourselves.
*/
static int
pppoe_sys_read_packet(int retv, struct strbuf *ctrl, struct strbuf *data,
int flags)
{
struct ppptun_control *ptc;
if (retv >= 0 && !(retv & MORECTL) && ctrl->len >= sizeof (uint32_t)) {
/* LINTED: alignment */
ptc = (struct ppptun_control *)ctrl->buf;
/* ptc_discrim is the first uint32_t of the structure. */
if (ptc->ptc_discrim == PPPOE_DISCRIM) {
retv = -1;
if (ctrl->len == sizeof (*ptc) &&
ptc->ptc_action == PTCA_CONTROL)
retv = handle_pppoe_input(&ptc->ptc_address,
ctrl, data);
if (retv < 0)
errno = EAGAIN;
return (retv);
}
}
/* Forward along to other plug-ins */
if (old_sys_read_packet != NULL &&
old_sys_read_packet != pppoe_sys_read_packet)
return ((*old_sys_read_packet)(retv, ctrl, data, flags));
return (retv);
}
/*
* Get an environment variable from the chat script.
*/
static int
saveenv(FILE *fd, const char *envname)
{
char envstr[1024];
int len;
if (fgets(envstr, sizeof (envstr), fd) == NULL)
return (-1);
len = strlen(envstr);
if (len <= 1)
return (0);
envstr[len-1] = '\0';
script_setenv(envname, envstr, 0);
return (1);
}
/*
* Read environment variables exported by chat script.
*/
static void
pppoe_device_pipe(int pipefd)
{
FILE *fd;
int i;
char envname[32];
fd = fdopen(pipefd, "r");
if (fd == NULL)
fatal("unable to open environment file: %m");
(void) saveenv(fd, "IF_AND_SERVICE");
(void) saveenv(fd, "SERVICE_NAME");
(void) saveenv(fd, "AC_NAME");
(void) saveenv(fd, "AC_MAC");
(void) saveenv(fd, "SESSION_ID");
for (i = 1; ; i++) {
slprintf(envname, sizeof (envname), "VENDOR_SPECIFIC_%d", i);
if (saveenv(fd, envname) <= 0)
break;
}
(void) fclose(fd);
}
void
plugin_init(void)
{
if (absmax_mtu > 1492)
absmax_mtu = 1492;
if (absmax_mru > 1492)
absmax_mru = 1492;
old_check_options = check_options_hook;
check_options_hook = pppoe_check_options;
old_updown_script = updown_script_hook;
updown_script_hook = pppoe_updown_script;
old_sys_read_packet = sys_read_packet_hook;
sys_read_packet_hook = pppoe_sys_read_packet;
device_pipe_hook = pppoe_device_pipe;
already_ppp = 1;
}