Commit | Line | Data |
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9d3a4132 SE |
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. */ | |
5 | ||
6 | #include "secnet.h" | |
7 | #include "util.h" | |
8 | #include "netlink.h" | |
9 | #include <stdio.h> | |
10 | #include <string.h> | |
11 | #include <unistd.h> | |
12 | ||
13 | #define SLIP_END 192 | |
14 | #define SLIP_ESC 219 | |
15 | #define SLIP_ESCEND 220 | |
16 | #define SLIP_ESCESC 221 | |
17 | ||
18 | /* Connection to the kernel through userv-ipif */ | |
19 | ||
20 | struct userv { | |
21 | struct netlink nl; | |
22 | int txfd; /* We transmit to userv */ | |
23 | int rxfd; /* We receive from userv */ | |
24 | string_t userv_path; | |
25 | string_t service_user; | |
26 | string_t service_name; | |
27 | uint32_t txbuflen; | |
28 | struct buffer_if *buff; /* We unstuff received packets into here | |
29 | and send them to the site code. */ | |
30 | bool_t pending_esc; | |
31 | netlink_deliver_fn *netlink_to_tunnel; | |
32 | }; | |
33 | ||
34 | static int userv_beforepoll(void *sst, struct pollfd *fds, int *nfds_io, | |
35 | int *timeout_io, const struct timeval *tv_now, | |
36 | uint64_t *now) | |
37 | { | |
38 | struct userv *st=sst; | |
39 | *nfds_io=2; | |
40 | fds[0].fd=st->txfd; | |
41 | fds[0].events=POLLERR; /* Might want to pick up POLLOUT sometime */ | |
42 | fds[1].fd=st->rxfd; | |
43 | fds[1].events=POLLIN|POLLERR|POLLHUP; | |
44 | return 0; | |
45 | } | |
46 | ||
47 | static void userv_afterpoll(void *sst, struct pollfd *fds, int nfds, | |
48 | const struct timeval *tv_now, uint64_t *now) | |
49 | { | |
50 | struct userv *st=sst; | |
51 | uint8_t rxbuf[DEFAULT_BUFSIZE]; | |
52 | int l,i; | |
53 | ||
54 | if (fds[1].revents&POLLERR) { | |
55 | Message(M_ERROR,"%s: userv_afterpoll: hup!\n",st->nl.name); | |
56 | } | |
57 | if (fds[1].revents&POLLIN) { | |
58 | l=read(st->rxfd,rxbuf,DEFAULT_BUFSIZE); | |
59 | if (l<0) { | |
60 | fatal_perror("%s: userv_afterpoll: read(rxfd)",st->nl.name); | |
61 | } | |
62 | if (l==0) { | |
63 | fatal("%s: userv_afterpoll: read(rxfd)=0; userv gone away?\n", | |
64 | st->nl.name); | |
65 | } | |
66 | /* XXX really crude unstuff code */ | |
67 | /* XXX check for buffer overflow */ | |
68 | BUF_ASSERT_USED(st->buff); | |
69 | for (i=0; i<l; i++) { | |
70 | if (st->pending_esc) { | |
71 | st->pending_esc=False; | |
72 | switch(rxbuf[i]) { | |
73 | case SLIP_ESCEND: | |
74 | *(uint8_t *)buf_append(st->buff,1)=SLIP_END; | |
75 | break; | |
76 | case SLIP_ESCESC: | |
77 | *(uint8_t *)buf_append(st->buff,1)=SLIP_ESC; | |
78 | break; | |
79 | default: | |
80 | fatal("userv_afterpoll: bad SLIP escape character\n"); | |
81 | } | |
82 | } else { | |
83 | switch (rxbuf[i]) { | |
84 | case SLIP_END: | |
85 | if (st->buff->size>0) { | |
86 | st->netlink_to_tunnel(&st->nl,NULL, | |
87 | st->buff); | |
88 | BUF_ALLOC(st->buff,"userv_afterpoll"); | |
89 | } | |
90 | buffer_init(st->buff,st->nl.max_start_pad); | |
91 | break; | |
92 | case SLIP_ESC: | |
93 | st->pending_esc=True; | |
94 | break; | |
95 | default: | |
96 | *(uint8_t *)buf_append(st->buff,1)=rxbuf[i]; | |
97 | break; | |
98 | } | |
99 | } | |
100 | } | |
101 | } | |
102 | } | |
103 | ||
104 | /* Send buf to the kernel. Free buf before returning. */ | |
105 | static void userv_deliver_to_kernel(void *sst, void *cid, | |
106 | struct buffer_if *buf) | |
107 | { | |
108 | struct userv *st=sst; | |
109 | uint8_t txbuf[DEFAULT_BUFSIZE]; | |
110 | uint8_t *i; | |
111 | uint32_t j; | |
112 | ||
113 | BUF_ASSERT_USED(buf); | |
114 | ||
115 | /* Spit the packet at userv-ipif: SLIP start marker, then | |
116 | bytestuff the packet, then SLIP end marker */ | |
117 | /* XXX crunchy bytestuff code */ | |
118 | j=0; | |
119 | txbuf[j++]=SLIP_END; | |
120 | for (i=buf->start; i<(buf->start+buf->size); i++) { | |
121 | switch (*i) { | |
122 | case SLIP_END: | |
123 | txbuf[j++]=SLIP_ESC; | |
124 | txbuf[j++]=SLIP_ESCEND; | |
125 | break; | |
126 | case SLIP_ESC: | |
127 | txbuf[j++]=SLIP_ESC; | |
128 | txbuf[j++]=SLIP_ESCESC; | |
129 | break; | |
130 | default: | |
131 | txbuf[j++]=*i; | |
132 | break; | |
133 | } | |
134 | } | |
135 | txbuf[j++]=SLIP_END; | |
136 | if (write(st->txfd,txbuf,j)<0) { | |
137 | fatal_perror("userv_deliver_to_kernel: write()"); | |
138 | } | |
139 | BUF_FREE(buf); | |
140 | } | |
141 | ||
142 | static void userv_phase_hook(void *sst, uint32_t newphase) | |
143 | { | |
144 | struct userv *st=sst; | |
145 | pid_t child; | |
146 | int c_stdin[2]; | |
147 | int c_stdout[2]; | |
148 | string_t addrs; | |
149 | string_t nets; | |
150 | string_t s; | |
151 | struct netlink_route *r; | |
152 | int i; | |
153 | ||
154 | /* This is where we actually invoke userv - all the networks we'll | |
155 | be using should already have been registered. */ | |
156 | ||
157 | addrs=safe_malloc(512,"userv_phase_hook:addrs"); | |
158 | snprintf(addrs,512,"%s,%s,%d,slip",ipaddr_to_string(st->nl.local_address), | |
159 | ipaddr_to_string(st->nl.secnet_address),st->nl.mtu); | |
160 | ||
161 | nets=safe_malloc(1024,"userv_phase_hook:nets"); | |
162 | *nets=0; | |
163 | r=st->nl.routes; | |
164 | for (i=0; i<st->nl.n_routes; i++) { | |
165 | if (r[i].up) { | |
166 | r[i].kup=True; | |
167 | s=subnet_to_string(&r[i].net); | |
168 | strcat(nets,s); | |
169 | strcat(nets,","); | |
170 | free(s); | |
171 | } | |
172 | } | |
173 | nets[strlen(nets)-1]=0; | |
174 | ||
175 | Message(M_INFO,"%s: about to invoke: %s %s %s %s %s\n",st->nl.name, | |
176 | st->userv_path,st->service_user,st->service_name,addrs,nets); | |
177 | ||
178 | /* Allocate buffer, plus space for padding. Make sure we end up | |
179 | with the start of the packet well-aligned. */ | |
180 | /* ALIGN(st->max_start_pad,16); */ | |
181 | /* ALIGN(st->max_end_pad,16); */ | |
182 | ||
183 | st->pending_esc=False; | |
184 | ||
185 | /* Invoke userv */ | |
186 | if (pipe(c_stdin)!=0) { | |
187 | fatal_perror("userv_phase_hook: pipe(c_stdin)"); | |
188 | } | |
189 | if (pipe(c_stdout)!=0) { | |
190 | fatal_perror("userv_phase_hook: pipe(c_stdout)"); | |
191 | } | |
192 | st->txfd=c_stdin[1]; | |
193 | st->rxfd=c_stdout[0]; | |
194 | ||
195 | child=fork(); | |
196 | if (child==-1) { | |
197 | fatal_perror("userv_phase_hook: fork()"); | |
198 | } | |
199 | if (child==0) { | |
200 | char **argv; | |
201 | ||
202 | /* We are the child. Modify our stdin and stdout, then exec userv */ | |
203 | dup2(c_stdin[0],0); | |
204 | dup2(c_stdout[1],1); | |
205 | close(c_stdin[1]); | |
206 | close(c_stdout[0]); | |
207 | ||
208 | /* The arguments are: | |
209 | userv | |
210 | service-user | |
211 | service-name | |
212 | local-addr,secnet-addr,mtu,protocol | |
213 | route1,route2,... */ | |
214 | argv=malloc(sizeof(*argv)*6); | |
215 | argv[0]=st->userv_path; | |
216 | argv[1]=st->service_user; | |
217 | argv[2]=st->service_name; | |
218 | argv[3]=addrs; | |
219 | argv[4]=nets; | |
220 | argv[5]=NULL; | |
221 | execvp(st->userv_path,argv); | |
222 | perror("netlink-userv-ipif: execvp"); | |
223 | ||
224 | exit(1); | |
225 | } | |
226 | /* We are the parent... */ | |
227 | ||
228 | /* Register for poll() */ | |
229 | register_for_poll(st, userv_beforepoll, userv_afterpoll, 2, st->nl.name); | |
230 | } | |
231 | ||
232 | static list_t *userv_apply(closure_t *self, struct cloc loc, dict_t *context, | |
233 | list_t *args) | |
234 | { | |
235 | struct userv *st; | |
236 | item_t *item; | |
237 | dict_t *dict; | |
238 | ||
239 | st=safe_malloc(sizeof(*st),"userv_apply"); | |
240 | ||
241 | /* First parameter must be a dict */ | |
242 | item=list_elem(args,0); | |
243 | if (!item || item->type!=t_dict) | |
244 | cfgfatal(loc,"userv-ipif","parameter must be a dictionary\n"); | |
245 | ||
246 | dict=item->data.dict; | |
247 | ||
248 | st->netlink_to_tunnel= | |
249 | netlink_init(&st->nl,st,loc,dict, | |
250 | "netlink-userv-ipif",NULL,userv_deliver_to_kernel); | |
251 | ||
252 | st->userv_path=dict_read_string(dict,"userv-path",False,"userv-netlink", | |
253 | loc); | |
254 | st->service_user=dict_read_string(dict,"service-user",False, | |
255 | "userv-netlink",loc); | |
256 | st->service_name=dict_read_string(dict,"service-name",False, | |
257 | "userv-netlink",loc); | |
258 | if (!st->userv_path) st->userv_path="userv"; | |
259 | if (!st->service_user) st->service_user="root"; | |
260 | if (!st->service_name) st->service_name="ipif"; | |
261 | st->buff=find_cl_if(dict,"buffer",CL_BUFFER,True,"userv-netlink",loc); | |
262 | BUF_ALLOC(st->buff,"netlink:userv_apply"); | |
263 | ||
264 | st->rxfd=-1; st->txfd=-1; | |
265 | add_hook(PHASE_DROPPRIV,userv_phase_hook,st); | |
266 | ||
267 | return new_closure(&st->nl.cl); | |
268 | } | |
269 | ||
270 | init_module slip_module; | |
271 | void slip_module(dict_t *dict) | |
272 | { | |
273 | add_closure(dict,"userv-ipif",userv_apply); | |
274 | #if 0 | |
275 | /* TODO */ | |
276 | add_closure(dict,"pty-slip",ptyslip_apply); | |
277 | add_closure(dict,"slipd",slipd_apply); | |
278 | #endif /* 0 */ | |
279 | } |