Commit | Line | Data |
---|---|---|
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 | 23 | #include "util.h" |
794f2398 | 24 | #include "unaligned.h" |
2fe58dfd SE |
25 | |
26 | static beforepoll_fn udp_beforepoll; | |
27 | static afterpoll_fn udp_afterpoll; | |
28 | static comm_request_notify_fn request_notify; | |
29 | static comm_release_notify_fn release_notify; | |
30 | static comm_sendmsg_fn udp_sendmsg; | |
31 | ||
32 | /* The UDP module exports a pure closure which can be used to construct a | |
33 | * UDP send/receive module. Arguments: | |
34 | */ | |
35 | ||
36 | struct notify_list { | |
37 | comm_notify_fn *fn; | |
38 | void *state; | |
39 | struct notify_list *next; | |
40 | }; | |
41 | ||
42 | struct udp { | |
43 | closure_t cl; | |
44 | struct comm_if ops; | |
45 | struct cloc loc; | |
baa06aeb | 46 | uint16_t port; |
2fe58dfd | 47 | int fd; |
b2a56f7c | 48 | string_t authbind; |
2fe58dfd SE |
49 | struct buffer_if *rbuf; |
50 | struct notify_list *notify; | |
51 | }; | |
52 | ||
53 | static int udp_beforepoll(void *state, struct pollfd *fds, int *nfds_io, | |
54 | int *timeout_io, const struct timeval *tv, | |
55 | uint64_t *now) | |
56 | { | |
57 | struct udp *st=state; | |
58 | if (*nfds_io<1) { | |
59 | *nfds_io=1; | |
60 | return ERANGE; | |
61 | } | |
62 | *nfds_io=1; | |
63 | fds->fd=st->fd; | |
64 | fds->events=POLLIN; | |
65 | return 0; | |
66 | } | |
67 | ||
68 | static void udp_afterpoll(void *state, struct pollfd *fds, int nfds, | |
69 | const struct timeval *tv, uint64_t *now) | |
70 | { | |
71 | struct udp *st=state; | |
72 | struct sockaddr_in from; | |
73 | int fromlen; | |
74 | struct notify_list *n; | |
75 | bool_t done; | |
76 | int rv; | |
77 | ||
78 | if (nfds && (fds->revents & POLLIN)) { | |
79 | do { | |
80 | fromlen=sizeof(from); | |
81 | BUF_ASSERT_FREE(st->rbuf); | |
82 | BUF_ALLOC(st->rbuf,"udp_afterpoll"); | |
83 | rv=recvfrom(st->fd, st->rbuf->start, st->rbuf->len, 0, | |
84 | (struct sockaddr *)&from, &fromlen); | |
85 | if (rv>0) { | |
86 | st->rbuf->size=rv; | |
87 | done=False; | |
88 | for (n=st->notify; n; n=n->next) { | |
89 | if (n->fn(n->state, st->rbuf, &from)) { | |
90 | done=True; | |
91 | break; | |
92 | } | |
93 | } | |
94 | if (!done) { | |
794f2398 | 95 | uint32_t source,dest; |
2fe58dfd | 96 | /* XXX manufacture and send NAK packet */ |
794f2398 SE |
97 | source=get_uint32(st->rbuf->start); /* Us */ |
98 | dest=get_uint32(st->rbuf->start+4); /* Them */ | |
99 | Message(M_INFO,"udp (port %d): sending NAK\n",st->port); | |
100 | buffer_init(st->rbuf,0); | |
101 | buf_append_uint32(st->rbuf,dest); | |
102 | buf_append_uint32(st->rbuf,source); | |
103 | buf_append_uint32(st->rbuf,0); /* NAK is msg type 0 */ | |
104 | sendto(st->fd, st->rbuf->start, st->rbuf->size, 0, | |
105 | (struct sockaddr *)&from, sizeof(from)); | |
2fe58dfd SE |
106 | BUF_FREE(st->rbuf); |
107 | } | |
108 | BUF_ASSERT_FREE(st->rbuf); | |
109 | } else { | |
110 | BUF_FREE(st->rbuf); | |
111 | } | |
112 | } while (rv>=0); | |
113 | } | |
114 | } | |
115 | ||
116 | static void request_notify(void *commst, void *nst, comm_notify_fn *fn) | |
117 | { | |
118 | struct udp *st=commst; | |
119 | struct notify_list *n; | |
120 | ||
121 | n=safe_malloc(sizeof(*n),"request_notify"); | |
122 | n->fn=fn; | |
123 | n->state=nst; | |
124 | n->next=st->notify; | |
125 | st->notify=n; | |
126 | } | |
127 | ||
128 | static void release_notify(void *commst, void *nst, comm_notify_fn *fn) | |
129 | { | |
130 | struct udp *st=commst; | |
131 | struct notify_list *n, **p, *t; | |
132 | ||
133 | /* XXX untested */ | |
134 | p=&st->notify; | |
135 | for (n=st->notify; n; ) | |
136 | { | |
137 | if (n->state==nst && n->fn==fn) { | |
138 | t=n; | |
139 | *p=n->next; | |
140 | n=n->next; | |
141 | free(t); | |
142 | } else { | |
143 | p=&n->next; | |
144 | n=n->next; | |
145 | } | |
146 | } | |
147 | } | |
148 | ||
149 | static bool_t udp_sendmsg(void *commst, struct buffer_if *buf, | |
150 | struct sockaddr_in *dest) | |
151 | { | |
152 | struct udp *st=commst; | |
153 | ||
154 | /* XXX fix error reporting */ | |
155 | sendto(st->fd, buf->start, buf->size, 0, | |
156 | (struct sockaddr *)dest, sizeof(*dest)); | |
157 | ||
158 | return True; | |
159 | } | |
160 | ||
baa06aeb SE |
161 | static void udp_phase_hook(void *sst, uint32_t new_phase) |
162 | { | |
163 | struct udp *st=sst; | |
164 | struct sockaddr_in addr; | |
165 | ||
166 | st->fd=socket(AF_INET, SOCK_DGRAM, 0); | |
167 | if (st->fd<0) { | |
168 | fatal_perror("udp (%s:%d): socket",st->loc.file,st->loc.line); | |
169 | } | |
170 | if (fcntl(st->fd, F_SETFL, fcntl(st->fd, F_GETFL)|O_NONBLOCK)==-1) { | |
171 | fatal_perror("udp (%s:%d): fcntl(set O_NONBLOCK)", | |
172 | st->loc.file,st->loc.line); | |
173 | } | |
174 | if (fcntl(st->fd, F_SETFD, FD_CLOEXEC)==-1) { | |
175 | fatal_perror("udp (%s:%d): fcntl(set FD_CLOEXEC)", | |
176 | st->loc.file,st->loc.line); | |
177 | } | |
178 | ||
179 | memset(&addr, 0, sizeof(addr)); | |
180 | addr.sin_family=AF_INET; | |
181 | addr.sin_port=htons(st->port); | |
b2a56f7c SE |
182 | if (st->authbind) { |
183 | pid_t c; | |
184 | int status; | |
185 | ||
186 | /* XXX this fork() and waitpid() business needs to be hidden | |
187 | in some system-specific library functions. */ | |
188 | c=fork(); | |
189 | if (c==-1) { | |
190 | fatal_perror("udp_phase_hook: fork() for authbind"); | |
191 | } | |
192 | if (c==0) { | |
193 | char *argv[4]; | |
194 | argv[0]=st->authbind; | |
195 | argv[1]="00000000"; | |
196 | argv[2]=alloca(8); | |
197 | if (!argv[2]) exit(ENOMEM); | |
198 | sprintf(argv[2],"%04X",htons(st->port)); | |
199 | argv[3]=NULL; | |
200 | dup2(st->fd,0); | |
201 | execvp(st->authbind,argv); | |
202 | exit(ENOEXEC); | |
203 | } | |
204 | waitpid(c,&status,0); | |
205 | if (WEXITSTATUS(status)!=0) { | |
206 | errno=WEXITSTATUS(status); | |
207 | fatal_perror("udp (%s:%d): authbind",st->loc.file,st->loc.line); | |
208 | } | |
209 | } else { | |
210 | if (bind(st->fd, (struct sockaddr *)&addr, sizeof(addr))!=0) { | |
211 | fatal_perror("udp (%s:%d): bind",st->loc.file,st->loc.line); | |
212 | } | |
baa06aeb SE |
213 | } |
214 | ||
215 | register_for_poll(st,udp_beforepoll,udp_afterpoll,1,"udp"); | |
216 | } | |
217 | ||
2fe58dfd SE |
218 | static list_t *udp_apply(closure_t *self, struct cloc loc, dict_t *context, |
219 | list_t *args) | |
220 | { | |
221 | struct udp *st; | |
222 | item_t *i; | |
223 | dict_t *d; | |
2fe58dfd SE |
224 | |
225 | st=safe_malloc(sizeof(*st),"udp_apply(st)"); | |
226 | st->loc=loc; | |
227 | st->cl.description="udp"; | |
228 | st->cl.type=CL_COMM; | |
229 | st->cl.apply=NULL; | |
230 | st->cl.interface=&st->ops; | |
231 | st->ops.st=st; | |
232 | st->ops.request_notify=request_notify; | |
233 | st->ops.release_notify=release_notify; | |
234 | st->ops.sendmsg=udp_sendmsg; | |
baa06aeb | 235 | st->port=0; |
2fe58dfd SE |
236 | |
237 | i=list_elem(args,0); | |
238 | if (!i || i->type!=t_dict) { | |
239 | cfgfatal(st->loc,"udp","first argument must be a dictionary\n"); | |
240 | } | |
241 | d=i->data.dict; | |
242 | ||
baa06aeb | 243 | st->port=dict_read_number(d,"port",True,"udp",st->loc,0); |
2fe58dfd | 244 | st->rbuf=find_cl_if(d,"buffer",CL_BUFFER,True,"udp",st->loc); |
b2a56f7c | 245 | st->authbind=dict_read_string(d,"authbind",False,"udp",st->loc); |
2fe58dfd | 246 | |
baa06aeb | 247 | add_hook(PHASE_GETRESOURCES,udp_phase_hook,st); |
2fe58dfd SE |
248 | |
249 | return new_closure(&st->cl); | |
250 | } | |
251 | ||
252 | init_module udp_module; | |
253 | void udp_module(dict_t *dict) | |
254 | { | |
255 | add_closure(dict,"udp",udp_apply); | |
256 | } |