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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> |
2fe58dfd SE |
22 | #include "util.h" |
23 | ||
24 | static beforepoll_fn udp_beforepoll; | |
25 | static afterpoll_fn udp_afterpoll; | |
26 | static comm_request_notify_fn request_notify; | |
27 | static comm_release_notify_fn release_notify; | |
28 | static comm_sendmsg_fn udp_sendmsg; | |
29 | ||
30 | /* The UDP module exports a pure closure which can be used to construct a | |
31 | * UDP send/receive module. Arguments: | |
32 | */ | |
33 | ||
34 | struct notify_list { | |
35 | comm_notify_fn *fn; | |
36 | void *state; | |
37 | struct notify_list *next; | |
38 | }; | |
39 | ||
40 | struct udp { | |
41 | closure_t cl; | |
42 | struct comm_if ops; | |
43 | struct cloc loc; | |
baa06aeb | 44 | uint16_t port; |
2fe58dfd SE |
45 | int fd; |
46 | struct buffer_if *rbuf; | |
47 | struct notify_list *notify; | |
48 | }; | |
49 | ||
50 | static int udp_beforepoll(void *state, struct pollfd *fds, int *nfds_io, | |
51 | int *timeout_io, const struct timeval *tv, | |
52 | uint64_t *now) | |
53 | { | |
54 | struct udp *st=state; | |
55 | if (*nfds_io<1) { | |
56 | *nfds_io=1; | |
57 | return ERANGE; | |
58 | } | |
59 | *nfds_io=1; | |
60 | fds->fd=st->fd; | |
61 | fds->events=POLLIN; | |
62 | return 0; | |
63 | } | |
64 | ||
65 | static void udp_afterpoll(void *state, struct pollfd *fds, int nfds, | |
66 | const struct timeval *tv, uint64_t *now) | |
67 | { | |
68 | struct udp *st=state; | |
69 | struct sockaddr_in from; | |
70 | int fromlen; | |
71 | struct notify_list *n; | |
72 | bool_t done; | |
73 | int rv; | |
74 | ||
75 | if (nfds && (fds->revents & POLLIN)) { | |
76 | do { | |
77 | fromlen=sizeof(from); | |
78 | BUF_ASSERT_FREE(st->rbuf); | |
79 | BUF_ALLOC(st->rbuf,"udp_afterpoll"); | |
80 | rv=recvfrom(st->fd, st->rbuf->start, st->rbuf->len, 0, | |
81 | (struct sockaddr *)&from, &fromlen); | |
82 | if (rv>0) { | |
83 | st->rbuf->size=rv; | |
84 | done=False; | |
85 | for (n=st->notify; n; n=n->next) { | |
86 | if (n->fn(n->state, st->rbuf, &from)) { | |
87 | done=True; | |
88 | break; | |
89 | } | |
90 | } | |
91 | if (!done) { | |
92 | /* XXX manufacture and send NAK packet */ | |
93 | Message(M_WARNING,"Need to send NAK\n"); | |
94 | BUF_FREE(st->rbuf); | |
95 | } | |
96 | BUF_ASSERT_FREE(st->rbuf); | |
97 | } else { | |
98 | BUF_FREE(st->rbuf); | |
99 | } | |
100 | } while (rv>=0); | |
101 | } | |
102 | } | |
103 | ||
104 | static void request_notify(void *commst, void *nst, comm_notify_fn *fn) | |
105 | { | |
106 | struct udp *st=commst; | |
107 | struct notify_list *n; | |
108 | ||
109 | n=safe_malloc(sizeof(*n),"request_notify"); | |
110 | n->fn=fn; | |
111 | n->state=nst; | |
112 | n->next=st->notify; | |
113 | st->notify=n; | |
114 | } | |
115 | ||
116 | static void release_notify(void *commst, void *nst, comm_notify_fn *fn) | |
117 | { | |
118 | struct udp *st=commst; | |
119 | struct notify_list *n, **p, *t; | |
120 | ||
121 | /* XXX untested */ | |
122 | p=&st->notify; | |
123 | for (n=st->notify; n; ) | |
124 | { | |
125 | if (n->state==nst && n->fn==fn) { | |
126 | t=n; | |
127 | *p=n->next; | |
128 | n=n->next; | |
129 | free(t); | |
130 | } else { | |
131 | p=&n->next; | |
132 | n=n->next; | |
133 | } | |
134 | } | |
135 | } | |
136 | ||
137 | static bool_t udp_sendmsg(void *commst, struct buffer_if *buf, | |
138 | struct sockaddr_in *dest) | |
139 | { | |
140 | struct udp *st=commst; | |
141 | ||
142 | /* XXX fix error reporting */ | |
143 | sendto(st->fd, buf->start, buf->size, 0, | |
144 | (struct sockaddr *)dest, sizeof(*dest)); | |
145 | ||
146 | return True; | |
147 | } | |
148 | ||
baa06aeb SE |
149 | static void udp_phase_hook(void *sst, uint32_t new_phase) |
150 | { | |
151 | struct udp *st=sst; | |
152 | struct sockaddr_in addr; | |
153 | ||
154 | st->fd=socket(AF_INET, SOCK_DGRAM, 0); | |
155 | if (st->fd<0) { | |
156 | fatal_perror("udp (%s:%d): socket",st->loc.file,st->loc.line); | |
157 | } | |
158 | if (fcntl(st->fd, F_SETFL, fcntl(st->fd, F_GETFL)|O_NONBLOCK)==-1) { | |
159 | fatal_perror("udp (%s:%d): fcntl(set O_NONBLOCK)", | |
160 | st->loc.file,st->loc.line); | |
161 | } | |
162 | if (fcntl(st->fd, F_SETFD, FD_CLOEXEC)==-1) { | |
163 | fatal_perror("udp (%s:%d): fcntl(set FD_CLOEXEC)", | |
164 | st->loc.file,st->loc.line); | |
165 | } | |
166 | ||
167 | memset(&addr, 0, sizeof(addr)); | |
168 | addr.sin_family=AF_INET; | |
169 | addr.sin_port=htons(st->port); | |
170 | if (bind(st->fd, (struct sockaddr *)&addr, sizeof(addr))!=0) { | |
171 | fatal_perror("udp (%s:%d): bind",st->loc.file,st->loc.line); | |
172 | } | |
173 | ||
174 | register_for_poll(st,udp_beforepoll,udp_afterpoll,1,"udp"); | |
175 | } | |
176 | ||
2fe58dfd SE |
177 | static list_t *udp_apply(closure_t *self, struct cloc loc, dict_t *context, |
178 | list_t *args) | |
179 | { | |
180 | struct udp *st; | |
181 | item_t *i; | |
182 | dict_t *d; | |
2fe58dfd SE |
183 | |
184 | st=safe_malloc(sizeof(*st),"udp_apply(st)"); | |
185 | st->loc=loc; | |
186 | st->cl.description="udp"; | |
187 | st->cl.type=CL_COMM; | |
188 | st->cl.apply=NULL; | |
189 | st->cl.interface=&st->ops; | |
190 | st->ops.st=st; | |
191 | st->ops.request_notify=request_notify; | |
192 | st->ops.release_notify=release_notify; | |
193 | st->ops.sendmsg=udp_sendmsg; | |
baa06aeb | 194 | st->port=0; |
2fe58dfd SE |
195 | |
196 | i=list_elem(args,0); | |
197 | if (!i || i->type!=t_dict) { | |
198 | cfgfatal(st->loc,"udp","first argument must be a dictionary\n"); | |
199 | } | |
200 | d=i->data.dict; | |
201 | ||
baa06aeb | 202 | st->port=dict_read_number(d,"port",True,"udp",st->loc,0); |
2fe58dfd SE |
203 | st->rbuf=find_cl_if(d,"buffer",CL_BUFFER,True,"udp",st->loc); |
204 | ||
baa06aeb | 205 | add_hook(PHASE_GETRESOURCES,udp_phase_hook,st); |
2fe58dfd SE |
206 | |
207 | return new_closure(&st->cl); | |
208 | } | |
209 | ||
210 | init_module udp_module; | |
211 | void udp_module(dict_t *dict) | |
212 | { | |
213 | add_closure(dict,"udp",udp_apply); | |
214 | } |