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Import release 0.1.5
[secnet] / udp.c
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1/* UDP send/receive module for secnet */
2
3/* This module enables sites to communicate by sending UDP
4 * packets. When an instance of the module is created we can
5 * optionally bind to a particular local IP address (not implemented
6 * yet).
7 *
8 * Sites register an interest in local port numbers for receiving
9 * packets, and can also send packets. We don't care about the source
10 * port number for sending packets.
11 *
12 * Packets are offered to registered receivers in turn. Once one
13 * accepts it, it isn't offered to any more. */
14
8689b3a9 15#include "secnet.h"
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16#include <stdio.h>
17#include <unistd.h>
18#include <fcntl.h>
19#include <string.h>
20#include <errno.h>
2fe58dfd 21#include <sys/socket.h>
b2a56f7c 22#include <sys/wait.h>
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23#include "util.h"
24
25static beforepoll_fn udp_beforepoll;
26static afterpoll_fn udp_afterpoll;
27static comm_request_notify_fn request_notify;
28static comm_release_notify_fn release_notify;
29static comm_sendmsg_fn udp_sendmsg;
30
31/* The UDP module exports a pure closure which can be used to construct a
32 * UDP send/receive module. Arguments:
33 */
34
35struct notify_list {
36 comm_notify_fn *fn;
37 void *state;
38 struct notify_list *next;
39};
40
41struct udp {
42 closure_t cl;
43 struct comm_if ops;
44 struct cloc loc;
baa06aeb 45 uint16_t port;
2fe58dfd 46 int fd;
b2a56f7c 47 string_t authbind;
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48 struct buffer_if *rbuf;
49 struct notify_list *notify;
50};
51
52static int udp_beforepoll(void *state, struct pollfd *fds, int *nfds_io,
53 int *timeout_io, const struct timeval *tv,
54 uint64_t *now)
55{
56 struct udp *st=state;
57 if (*nfds_io<1) {
58 *nfds_io=1;
59 return ERANGE;
60 }
61 *nfds_io=1;
62 fds->fd=st->fd;
63 fds->events=POLLIN;
64 return 0;
65}
66
67static void udp_afterpoll(void *state, struct pollfd *fds, int nfds,
68 const struct timeval *tv, uint64_t *now)
69{
70 struct udp *st=state;
71 struct sockaddr_in from;
72 int fromlen;
73 struct notify_list *n;
74 bool_t done;
75 int rv;
76
77 if (nfds && (fds->revents & POLLIN)) {
78 do {
79 fromlen=sizeof(from);
80 BUF_ASSERT_FREE(st->rbuf);
81 BUF_ALLOC(st->rbuf,"udp_afterpoll");
82 rv=recvfrom(st->fd, st->rbuf->start, st->rbuf->len, 0,
83 (struct sockaddr *)&from, &fromlen);
84 if (rv>0) {
85 st->rbuf->size=rv;
86 done=False;
87 for (n=st->notify; n; n=n->next) {
88 if (n->fn(n->state, st->rbuf, &from)) {
89 done=True;
90 break;
91 }
92 }
93 if (!done) {
94 /* XXX manufacture and send NAK packet */
95 Message(M_WARNING,"Need to send NAK\n");
96 BUF_FREE(st->rbuf);
97 }
98 BUF_ASSERT_FREE(st->rbuf);
99 } else {
100 BUF_FREE(st->rbuf);
101 }
102 } while (rv>=0);
103 }
104}
105
106static void request_notify(void *commst, void *nst, comm_notify_fn *fn)
107{
108 struct udp *st=commst;
109 struct notify_list *n;
110
111 n=safe_malloc(sizeof(*n),"request_notify");
112 n->fn=fn;
113 n->state=nst;
114 n->next=st->notify;
115 st->notify=n;
116}
117
118static void release_notify(void *commst, void *nst, comm_notify_fn *fn)
119{
120 struct udp *st=commst;
121 struct notify_list *n, **p, *t;
122
123 /* XXX untested */
124 p=&st->notify;
125 for (n=st->notify; n; )
126 {
127 if (n->state==nst && n->fn==fn) {
128 t=n;
129 *p=n->next;
130 n=n->next;
131 free(t);
132 } else {
133 p=&n->next;
134 n=n->next;
135 }
136 }
137}
138
139static bool_t udp_sendmsg(void *commst, struct buffer_if *buf,
140 struct sockaddr_in *dest)
141{
142 struct udp *st=commst;
143
144 /* XXX fix error reporting */
145 sendto(st->fd, buf->start, buf->size, 0,
146 (struct sockaddr *)dest, sizeof(*dest));
147
148 return True;
149}
150
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151static void udp_phase_hook(void *sst, uint32_t new_phase)
152{
153 struct udp *st=sst;
154 struct sockaddr_in addr;
155
156 st->fd=socket(AF_INET, SOCK_DGRAM, 0);
157 if (st->fd<0) {
158 fatal_perror("udp (%s:%d): socket",st->loc.file,st->loc.line);
159 }
160 if (fcntl(st->fd, F_SETFL, fcntl(st->fd, F_GETFL)|O_NONBLOCK)==-1) {
161 fatal_perror("udp (%s:%d): fcntl(set O_NONBLOCK)",
162 st->loc.file,st->loc.line);
163 }
164 if (fcntl(st->fd, F_SETFD, FD_CLOEXEC)==-1) {
165 fatal_perror("udp (%s:%d): fcntl(set FD_CLOEXEC)",
166 st->loc.file,st->loc.line);
167 }
168
169 memset(&addr, 0, sizeof(addr));
170 addr.sin_family=AF_INET;
171 addr.sin_port=htons(st->port);
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172 if (st->authbind) {
173 pid_t c;
174 int status;
175
176 /* XXX this fork() and waitpid() business needs to be hidden
177 in some system-specific library functions. */
178 c=fork();
179 if (c==-1) {
180 fatal_perror("udp_phase_hook: fork() for authbind");
181 }
182 if (c==0) {
183 char *argv[4];
184 argv[0]=st->authbind;
185 argv[1]="00000000";
186 argv[2]=alloca(8);
187 if (!argv[2]) exit(ENOMEM);
188 sprintf(argv[2],"%04X",htons(st->port));
189 argv[3]=NULL;
190 dup2(st->fd,0);
191 execvp(st->authbind,argv);
192 exit(ENOEXEC);
193 }
194 waitpid(c,&status,0);
195 if (WEXITSTATUS(status)!=0) {
196 errno=WEXITSTATUS(status);
197 fatal_perror("udp (%s:%d): authbind",st->loc.file,st->loc.line);
198 }
199 } else {
200 if (bind(st->fd, (struct sockaddr *)&addr, sizeof(addr))!=0) {
201 fatal_perror("udp (%s:%d): bind",st->loc.file,st->loc.line);
202 }
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203 }
204
205 register_for_poll(st,udp_beforepoll,udp_afterpoll,1,"udp");
206}
207
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208static list_t *udp_apply(closure_t *self, struct cloc loc, dict_t *context,
209 list_t *args)
210{
211 struct udp *st;
212 item_t *i;
213 dict_t *d;
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214
215 st=safe_malloc(sizeof(*st),"udp_apply(st)");
216 st->loc=loc;
217 st->cl.description="udp";
218 st->cl.type=CL_COMM;
219 st->cl.apply=NULL;
220 st->cl.interface=&st->ops;
221 st->ops.st=st;
222 st->ops.request_notify=request_notify;
223 st->ops.release_notify=release_notify;
224 st->ops.sendmsg=udp_sendmsg;
baa06aeb 225 st->port=0;
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226
227 i=list_elem(args,0);
228 if (!i || i->type!=t_dict) {
229 cfgfatal(st->loc,"udp","first argument must be a dictionary\n");
230 }
231 d=i->data.dict;
232
baa06aeb 233 st->port=dict_read_number(d,"port",True,"udp",st->loc,0);
2fe58dfd 234 st->rbuf=find_cl_if(d,"buffer",CL_BUFFER,True,"udp",st->loc);
b2a56f7c 235 st->authbind=dict_read_string(d,"authbind",False,"udp",st->loc);
2fe58dfd 236
baa06aeb 237 add_hook(PHASE_GETRESOURCES,udp_phase_hook,st);
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238
239 return new_closure(&st->cl);
240}
241
242init_module udp_module;
243void udp_module(dict_t *dict)
244{
245 add_closure(dict,"udp",udp_apply);
246}