1 /* When dealing with SLIP (to a pty, or ipif) we have separate rx, tx
2 and client buffers. When receiving we may read() any amount, not
3 just whole packets. When transmitting we need to bytestuff anyway,
4 and may be part-way through receiving. */
10 #include "unaligned.h"
19 #define SLIP_ESCEND 220
20 #define SLIP_ESCESC 221
24 struct buffer_if *buff; /* We unstuff received packets into here
25 and send them to the netlink code. */
27 bool_t ignoring_packet; /* If this packet was corrupt or overlong,
28 we ignore everything up to the next END */
29 netlink_deliver_fn *netlink_to_tunnel;
32 /* Generic SLIP mangling code */
34 static void slip_write(int fd, const uint8_t *p, size_t l)
37 ssize_t written=write(fd,p,l);
41 } else if (iswouldblock(errno)) {
42 lg_perror(0,"slip",0,M_ERR,errno,"write() (packet(s) lost)");
45 fatal_perror("slip_stuff: write()");
49 assert((size_t)written<=l);
55 static void slip_stuff(struct slip *st, struct buffer_if *buf, int fd)
57 uint8_t txbuf[DEFAULT_BUFSIZE];
63 /* There's probably a much more efficient way of implementing this */
65 for (i=buf->start; i<(buf->start+buf->size); i++) {
69 txbuf[j++]=SLIP_ESCEND;
73 txbuf[j++]=SLIP_ESCESC;
79 if ((j+2)>DEFAULT_BUFSIZE) {
80 slip_write(fd,txbuf,j);
85 slip_write(fd,txbuf,j);
89 static void slip_unstuff(struct slip *st, uint8_t *buf, uint32_t l)
93 BUF_ASSERT_USED(st->buff);
96 enum { OUTPUT_END = 256, OUTPUT_NOTHING = 257 };
99 buffer_init(st->buff,calculate_max_start_pad());
101 if (st->pending_esc) {
102 st->pending_esc=False;
111 if (!st->ignoring_packet) {
112 Message(M_WARNING, "userv_afterpoll: bad SLIP escape"
113 " character, dropping packet\n");
115 st->ignoring_packet=True;
116 outputchr=OUTPUT_NOTHING;
122 outputchr=OUTPUT_END;
125 st->pending_esc=True;
126 outputchr=OUTPUT_NOTHING;
134 if (st->ignoring_packet) {
135 if (outputchr == OUTPUT_END) {
136 st->ignoring_packet=False;
140 if (outputchr == OUTPUT_END) {
141 if (st->buff->size>0) {
142 st->netlink_to_tunnel(&st->nl,st->buff);
143 BUF_ALLOC(st->buff,"userv_afterpoll");
146 } else if (outputchr != OUTPUT_NOTHING) {
147 if (buf_remaining_space(st->buff)) {
148 buf_append_uint8(st->buff,outputchr);
150 Message(M_WARNING, "userv_afterpoll: dropping overlong"
152 st->ignoring_packet=True;
159 static void slip_init(struct slip *st, struct cloc loc, dict_t *dict,
160 cstring_t name, netlink_deliver_fn *to_host)
162 st->netlink_to_tunnel=
163 netlink_init(&st->nl,st,loc,dict,
164 "netlink-userv-ipif",NULL,to_host);
165 st->buff=find_cl_if(dict,"buffer",CL_BUFFER,True,"name",loc);
166 BUF_ALLOC(st->buff,"slip_init");
167 st->pending_esc=False;
168 st->ignoring_packet=False;
171 /* Connection to the kernel through userv-ipif */
175 int txfd; /* We transmit to userv */
176 int rxfd; /* We receive from userv */
177 cstring_t userv_path;
178 cstring_t service_user;
179 cstring_t service_name;
181 bool_t expecting_userv_exit;
184 static int userv_beforepoll(void *sst, struct pollfd *fds, int *nfds_io,
187 struct userv *st=sst;
190 BEFOREPOLL_WANT_FDS(2);
192 fds[0].events=0; /* Might want to pick up POLLOUT sometime */
194 fds[1].events=POLLIN;
196 BEFOREPOLL_WANT_FDS(0);
201 static void userv_afterpoll(void *sst, struct pollfd *fds, int nfds)
203 struct userv *st=sst;
204 uint8_t rxbuf[DEFAULT_BUFSIZE];
209 if (fds[1].revents&POLLERR) {
210 Message(M_ERR,"%s: userv_afterpoll: POLLERR!\n",st->slip.nl.name);
212 if (fds[1].revents&POLLIN) {
213 l=read(st->rxfd,rxbuf,DEFAULT_BUFSIZE);
215 if (errno!=EINTR && !iswouldblock(errno))
216 fatal_perror("%s: userv_afterpoll: read(rxfd)",
219 fatal("%s: userv_afterpoll: read(rxfd)=0; userv gone away?",
221 } else slip_unstuff(&st->slip,rxbuf,l);
225 /* Send buf to the kernel. Free buf before returning. */
226 static void userv_deliver_to_kernel(void *sst, struct buffer_if *buf)
228 struct userv *st=sst;
230 if (buf->size > st->slip.nl.mtu) {
231 Message(M_ERR,"%s: packet of size %"PRIu32" exceeds mtu %"PRIu32":"
232 " cannot be injected into kernel, dropped\n",
233 st->slip.nl.name, buf->size, st->slip.nl.mtu);
238 slip_stuff(&st->slip,buf,st->txfd);
241 static void userv_userv_callback(void *sst, pid_t pid, int status)
243 struct userv *st=sst;
246 Message(M_WARNING,"userv_callback called unexpectedly with pid %d "
247 "(expected %d)\n",pid,st->pid);
250 if (!(st->expecting_userv_exit &&
252 (WIFSIGNALED(status) && WTERMSIG(status)==SIGTERM)))) {
253 lg_exitstatus(0,st->slip.nl.name,0,
254 st->expecting_userv_exit ? M_WARNING : M_FATAL,
260 struct userv_entry_rec {
265 /* XXX perhaps we should collect and log stderr? */
268 static void userv_entry(void *sst)
270 struct userv_entry_rec *st=sst;
276 execvp(st->path,(char *const*)st->argv);
277 perror("userv-entry: execvp()");
281 static void userv_invoke_userv(struct userv *st)
283 struct userv_entry_rec er[1];
288 struct netlink_client *r;
289 struct ipset *allnets;
290 struct subnet_list *snets;
295 fatal("userv_invoke_userv: already running");
298 /* This is where we actually invoke userv - all the networks we'll
299 be using should already have been registered. */
302 snprintf(addrs,sizeof(addrs),"%s,%s,%d,slip",
303 ipaddr_to_string(st->slip.nl.local_address),
304 ipaddr_to_string(st->slip.nl.secnet_address),st->slip.nl.mtu);
307 for (r=st->slip.nl.clients; r; r=r->next) {
308 if (r->link_quality > LINK_QUALITY_UNUSED) {
311 nan=ipset_union(allnets,r->networks);
316 snets=ipset_to_subnet_list(allnets);
318 nets=safe_malloc(20*snets->entries,"userv_invoke_userv:nets");
320 for (i=0; i<snets->entries; i++) {
321 s=subnet_to_string(snets->list[i]);
325 nets[strlen(nets)-1]=0;
326 subnet_list_free(snets);
328 Message(M_INFO,"%s: about to invoke: %s %s %s %s %s\n",st->slip.nl.name,
329 st->userv_path,st->service_user,st->service_name,addrs,nets);
331 st->slip.pending_esc=False;
334 pipe_cloexec(c_stdin);
335 pipe_cloexec(c_stdout);
337 st->rxfd=c_stdout[0];
341 /* The arguments are:
345 local-addr,secnet-addr,mtu,protocol
347 const char *er_argv[6];
349 er->argv[0]=st->userv_path;
350 er->argv[1]=st->service_user;
351 er->argv[2]=st->service_name;
355 er->path=st->userv_path;
357 st->pid=makesubproc(userv_entry, userv_userv_callback,
358 er, st, st->slip.nl.name);
362 Message(M_INFO,"%s: userv-ipif pid is %d\n",st->slip.nl.name,st->pid);
363 /* Read a single character from the pipe to confirm userv-ipif is
364 running. If we get a SIGCHLD at this point then we'll get EINTR. */
365 if ((nread=read(st->rxfd,&confirm,1))!=1) {
367 Message(M_WARNING,"%s: read of confirmation byte was "
368 "interrupted\n",st->slip.nl.name);
371 fatal_perror("%s: error reading confirmation byte",
374 fatal("%s: unexpected EOF instead of confirmation byte"
375 " - userv ipif failed?", st->slip.nl.name);
379 if (confirm!=SLIP_END) {
380 fatal("%s: bad confirmation byte %d from userv-ipif",
381 st->slip.nl.name,confirm);
384 setnonblock(st->txfd);
385 setnonblock(st->rxfd);
388 static void userv_kill_userv(struct userv *st)
391 kill(-st->pid,SIGTERM);
392 st->expecting_userv_exit=True;
396 static void userv_phase_hook(void *sst, uint32_t newphase)
398 struct userv *st=sst;
399 /* We must wait until signal processing has started before forking
401 if (newphase==PHASE_RUN) {
402 userv_invoke_userv(st);
403 /* Register for poll() */
404 register_for_poll(st, userv_beforepoll, userv_afterpoll,
407 if (newphase==PHASE_SHUTDOWN) {
408 userv_kill_userv(st);
412 static list_t *userv_apply(closure_t *self, struct cloc loc, dict_t *context,
419 st=safe_malloc(sizeof(*st),"userv_apply");
421 /* First parameter must be a dict */
422 item=list_elem(args,0);
423 if (!item || item->type!=t_dict)
424 cfgfatal(loc,"userv-ipif","parameter must be a dictionary\n");
426 dict=item->data.dict;
428 slip_init(&st->slip,loc,dict,"netlink-userv-ipif",
429 userv_deliver_to_kernel);
431 st->userv_path=dict_read_string(dict,"userv-path",False,"userv-netlink",
433 st->service_user=dict_read_string(dict,"service-user",False,
434 "userv-netlink",loc);
435 st->service_name=dict_read_string(dict,"service-name",False,
436 "userv-netlink",loc);
437 if (!st->userv_path) st->userv_path="userv";
438 if (!st->service_user) st->service_user="root";
439 if (!st->service_name) st->service_name="ipif";
440 st->rxfd=-1; st->txfd=-1;
442 st->expecting_userv_exit=False;
443 add_hook(PHASE_RUN,userv_phase_hook,st);
444 add_hook(PHASE_SHUTDOWN,userv_phase_hook,st);
446 return new_closure(&st->slip.nl.cl);
449 void slip_module(dict_t *dict)
451 add_closure(dict,"userv-ipif",userv_apply);