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2fe58dfd SE |
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" |
2fe58dfd SE |
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> |
2fe58dfd SE |
23 | #include "util.h" |
24 | ||
25 | static beforepoll_fn udp_beforepoll; | |
26 | static afterpoll_fn udp_afterpoll; | |
27 | static comm_request_notify_fn request_notify; | |
28 | static comm_release_notify_fn release_notify; | |
29 | static 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 | ||
35 | struct notify_list { | |
36 | comm_notify_fn *fn; | |
37 | void *state; | |
38 | struct notify_list *next; | |
39 | }; | |
40 | ||
41 | struct 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; |
2fe58dfd SE |
48 | struct buffer_if *rbuf; |
49 | struct notify_list *notify; | |
50 | }; | |
51 | ||
52 | static 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 | ||
67 | static 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 | ||
106 | static 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 | ||
118 | static 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 | ||
139 | static 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 | ||
baa06aeb SE |
151 | static 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); | |
b2a56f7c SE |
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 | } | |
baa06aeb SE |
203 | } |
204 | ||
205 | register_for_poll(st,udp_beforepoll,udp_afterpoll,1,"udp"); | |
206 | } | |
207 | ||
2fe58dfd SE |
208 | static 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; | |
2fe58dfd SE |
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; |
2fe58dfd SE |
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); |
2fe58dfd SE |
238 | |
239 | return new_closure(&st->cl); | |
240 | } | |
241 | ||
242 | init_module udp_module; | |
243 | void udp_module(dict_t *dict) | |
244 | { | |
245 | add_closure(dict,"udp",udp_apply); | |
246 | } |