x25_subr.c 9.1 KB

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  1. /*
  2. * X.25 Packet Layer release 002
  3. *
  4. * This is ALPHA test software. This code may break your machine,
  5. * randomly fail to work with new releases, misbehave and/or generally
  6. * screw up. It might even work.
  7. *
  8. * This code REQUIRES 2.1.15 or higher
  9. *
  10. * This module:
  11. * This module is free software; you can redistribute it and/or
  12. * modify it under the terms of the GNU General Public License
  13. * as published by the Free Software Foundation; either version
  14. * 2 of the License, or (at your option) any later version.
  15. *
  16. * History
  17. * X.25 001 Jonathan Naylor Started coding.
  18. * X.25 002 Jonathan Naylor Centralised disconnection processing.
  19. * mar/20/00 Daniela Squassoni Disabling/enabling of facilities
  20. * negotiation.
  21. * jun/24/01 Arnaldo C. Melo use skb_queue_purge, cleanups
  22. * apr/04/15 Shaun Pereira Fast select with no
  23. * restriction on response.
  24. */
  25. #include <linux/kernel.h>
  26. #include <linux/string.h>
  27. #include <linux/skbuff.h>
  28. #include <net/sock.h>
  29. #include <net/tcp_states.h>
  30. #include <net/x25.h>
  31. /*
  32. * This routine purges all of the queues of frames.
  33. */
  34. void x25_clear_queues(struct sock *sk)
  35. {
  36. struct x25_sock *x25 = x25_sk(sk);
  37. skb_queue_purge(&sk->sk_write_queue);
  38. skb_queue_purge(&x25->ack_queue);
  39. skb_queue_purge(&x25->interrupt_in_queue);
  40. skb_queue_purge(&x25->interrupt_out_queue);
  41. skb_queue_purge(&x25->fragment_queue);
  42. }
  43. /*
  44. * This routine purges the input queue of those frames that have been
  45. * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the
  46. * SDL diagram.
  47. */
  48. void x25_frames_acked(struct sock *sk, unsigned short nr)
  49. {
  50. struct sk_buff *skb;
  51. struct x25_sock *x25 = x25_sk(sk);
  52. int modulus = x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS;
  53. /*
  54. * Remove all the ack-ed frames from the ack queue.
  55. */
  56. if (x25->va != nr)
  57. while (skb_peek(&x25->ack_queue) && x25->va != nr) {
  58. skb = skb_dequeue(&x25->ack_queue);
  59. kfree_skb(skb);
  60. x25->va = (x25->va + 1) % modulus;
  61. }
  62. }
  63. void x25_requeue_frames(struct sock *sk)
  64. {
  65. struct sk_buff *skb, *skb_prev = NULL;
  66. /*
  67. * Requeue all the un-ack-ed frames on the output queue to be picked
  68. * up by x25_kick. This arrangement handles the possibility of an empty
  69. * output queue.
  70. */
  71. while ((skb = skb_dequeue(&x25_sk(sk)->ack_queue)) != NULL) {
  72. if (!skb_prev)
  73. skb_queue_head(&sk->sk_write_queue, skb);
  74. else
  75. skb_append(skb_prev, skb, &sk->sk_write_queue);
  76. skb_prev = skb;
  77. }
  78. }
  79. /*
  80. * Validate that the value of nr is between va and vs. Return true or
  81. * false for testing.
  82. */
  83. int x25_validate_nr(struct sock *sk, unsigned short nr)
  84. {
  85. struct x25_sock *x25 = x25_sk(sk);
  86. unsigned short vc = x25->va;
  87. int modulus = x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS;
  88. while (vc != x25->vs) {
  89. if (nr == vc)
  90. return 1;
  91. vc = (vc + 1) % modulus;
  92. }
  93. return nr == x25->vs ? 1 : 0;
  94. }
  95. /*
  96. * This routine is called when the packet layer internally generates a
  97. * control frame.
  98. */
  99. void x25_write_internal(struct sock *sk, int frametype)
  100. {
  101. struct x25_sock *x25 = x25_sk(sk);
  102. struct sk_buff *skb;
  103. unsigned char *dptr;
  104. unsigned char facilities[X25_MAX_FAC_LEN];
  105. unsigned char addresses[1 + X25_ADDR_LEN];
  106. unsigned char lci1, lci2;
  107. /*
  108. * Default safe frame size.
  109. */
  110. int len = X25_MAX_L2_LEN + X25_EXT_MIN_LEN;
  111. /*
  112. * Adjust frame size.
  113. */
  114. switch (frametype) {
  115. case X25_CALL_REQUEST:
  116. len += 1 + X25_ADDR_LEN + X25_MAX_FAC_LEN +
  117. X25_MAX_CUD_LEN;
  118. break;
  119. case X25_CALL_ACCEPTED: /* fast sel with no restr on resp */
  120. if(x25->facilities.reverse & 0x80) {
  121. len += 1 + X25_MAX_FAC_LEN + X25_MAX_CUD_LEN;
  122. } else {
  123. len += 1 + X25_MAX_FAC_LEN;
  124. }
  125. break;
  126. case X25_CLEAR_REQUEST:
  127. case X25_RESET_REQUEST:
  128. len += 2;
  129. break;
  130. case X25_RR:
  131. case X25_RNR:
  132. case X25_REJ:
  133. case X25_CLEAR_CONFIRMATION:
  134. case X25_INTERRUPT_CONFIRMATION:
  135. case X25_RESET_CONFIRMATION:
  136. break;
  137. default:
  138. printk(KERN_ERR "X.25: invalid frame type %02X\n",
  139. frametype);
  140. return;
  141. }
  142. if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
  143. return;
  144. /*
  145. * Space for Ethernet and 802.2 LLC headers.
  146. */
  147. skb_reserve(skb, X25_MAX_L2_LEN);
  148. /*
  149. * Make space for the GFI and LCI, and fill them in.
  150. */
  151. dptr = skb_put(skb, 2);
  152. lci1 = (x25->lci >> 8) & 0x0F;
  153. lci2 = (x25->lci >> 0) & 0xFF;
  154. if (x25->neighbour->extended) {
  155. *dptr++ = lci1 | X25_GFI_EXTSEQ;
  156. *dptr++ = lci2;
  157. } else {
  158. *dptr++ = lci1 | X25_GFI_STDSEQ;
  159. *dptr++ = lci2;
  160. }
  161. /*
  162. * Now fill in the frame type specific information.
  163. */
  164. switch (frametype) {
  165. case X25_CALL_REQUEST:
  166. dptr = skb_put(skb, 1);
  167. *dptr++ = X25_CALL_REQUEST;
  168. len = x25_addr_aton(addresses, &x25->dest_addr,
  169. &x25->source_addr);
  170. dptr = skb_put(skb, len);
  171. memcpy(dptr, addresses, len);
  172. len = x25_create_facilities(facilities,
  173. &x25->facilities,
  174. &x25->dte_facilities,
  175. x25->neighbour->global_facil_mask);
  176. dptr = skb_put(skb, len);
  177. memcpy(dptr, facilities, len);
  178. dptr = skb_put(skb, x25->calluserdata.cudlength);
  179. memcpy(dptr, x25->calluserdata.cuddata,
  180. x25->calluserdata.cudlength);
  181. x25->calluserdata.cudlength = 0;
  182. break;
  183. case X25_CALL_ACCEPTED:
  184. dptr = skb_put(skb, 2);
  185. *dptr++ = X25_CALL_ACCEPTED;
  186. *dptr++ = 0x00; /* Address lengths */
  187. len = x25_create_facilities(facilities,
  188. &x25->facilities,
  189. &x25->dte_facilities,
  190. x25->vc_facil_mask);
  191. dptr = skb_put(skb, len);
  192. memcpy(dptr, facilities, len);
  193. /* fast select with no restriction on response
  194. allows call user data. Userland must
  195. ensure it is ours and not theirs */
  196. if(x25->facilities.reverse & 0x80) {
  197. dptr = skb_put(skb,
  198. x25->calluserdata.cudlength);
  199. memcpy(dptr, x25->calluserdata.cuddata,
  200. x25->calluserdata.cudlength);
  201. }
  202. x25->calluserdata.cudlength = 0;
  203. break;
  204. case X25_CLEAR_REQUEST:
  205. case X25_RESET_REQUEST:
  206. dptr = skb_put(skb, 3);
  207. *dptr++ = frametype;
  208. *dptr++ = 0x00; /* XXX */
  209. *dptr++ = 0x00; /* XXX */
  210. break;
  211. case X25_RR:
  212. case X25_RNR:
  213. case X25_REJ:
  214. if (x25->neighbour->extended) {
  215. dptr = skb_put(skb, 2);
  216. *dptr++ = frametype;
  217. *dptr++ = (x25->vr << 1) & 0xFE;
  218. } else {
  219. dptr = skb_put(skb, 1);
  220. *dptr = frametype;
  221. *dptr++ |= (x25->vr << 5) & 0xE0;
  222. }
  223. break;
  224. case X25_CLEAR_CONFIRMATION:
  225. case X25_INTERRUPT_CONFIRMATION:
  226. case X25_RESET_CONFIRMATION:
  227. dptr = skb_put(skb, 1);
  228. *dptr = frametype;
  229. break;
  230. }
  231. x25_transmit_link(skb, x25->neighbour);
  232. }
  233. /*
  234. * Unpick the contents of the passed X.25 Packet Layer frame.
  235. */
  236. int x25_decode(struct sock *sk, struct sk_buff *skb, int *ns, int *nr, int *q,
  237. int *d, int *m)
  238. {
  239. struct x25_sock *x25 = x25_sk(sk);
  240. unsigned char *frame = skb->data;
  241. *ns = *nr = *q = *d = *m = 0;
  242. switch (frame[2]) {
  243. case X25_CALL_REQUEST:
  244. case X25_CALL_ACCEPTED:
  245. case X25_CLEAR_REQUEST:
  246. case X25_CLEAR_CONFIRMATION:
  247. case X25_INTERRUPT:
  248. case X25_INTERRUPT_CONFIRMATION:
  249. case X25_RESET_REQUEST:
  250. case X25_RESET_CONFIRMATION:
  251. case X25_RESTART_REQUEST:
  252. case X25_RESTART_CONFIRMATION:
  253. case X25_REGISTRATION_REQUEST:
  254. case X25_REGISTRATION_CONFIRMATION:
  255. case X25_DIAGNOSTIC:
  256. return frame[2];
  257. }
  258. if (x25->neighbour->extended) {
  259. if (frame[2] == X25_RR ||
  260. frame[2] == X25_RNR ||
  261. frame[2] == X25_REJ) {
  262. *nr = (frame[3] >> 1) & 0x7F;
  263. return frame[2];
  264. }
  265. } else {
  266. if ((frame[2] & 0x1F) == X25_RR ||
  267. (frame[2] & 0x1F) == X25_RNR ||
  268. (frame[2] & 0x1F) == X25_REJ) {
  269. *nr = (frame[2] >> 5) & 0x07;
  270. return frame[2] & 0x1F;
  271. }
  272. }
  273. if (x25->neighbour->extended) {
  274. if ((frame[2] & 0x01) == X25_DATA) {
  275. *q = (frame[0] & X25_Q_BIT) == X25_Q_BIT;
  276. *d = (frame[0] & X25_D_BIT) == X25_D_BIT;
  277. *m = (frame[3] & X25_EXT_M_BIT) == X25_EXT_M_BIT;
  278. *nr = (frame[3] >> 1) & 0x7F;
  279. *ns = (frame[2] >> 1) & 0x7F;
  280. return X25_DATA;
  281. }
  282. } else {
  283. if ((frame[2] & 0x01) == X25_DATA) {
  284. *q = (frame[0] & X25_Q_BIT) == X25_Q_BIT;
  285. *d = (frame[0] & X25_D_BIT) == X25_D_BIT;
  286. *m = (frame[2] & X25_STD_M_BIT) == X25_STD_M_BIT;
  287. *nr = (frame[2] >> 5) & 0x07;
  288. *ns = (frame[2] >> 1) & 0x07;
  289. return X25_DATA;
  290. }
  291. }
  292. printk(KERN_DEBUG "X.25: invalid PLP frame %02X %02X %02X\n",
  293. frame[0], frame[1], frame[2]);
  294. return X25_ILLEGAL;
  295. }
  296. void x25_disconnect(struct sock *sk, int reason, unsigned char cause,
  297. unsigned char diagnostic)
  298. {
  299. struct x25_sock *x25 = x25_sk(sk);
  300. x25_clear_queues(sk);
  301. x25_stop_timer(sk);
  302. x25->lci = 0;
  303. x25->state = X25_STATE_0;
  304. x25->causediag.cause = cause;
  305. x25->causediag.diagnostic = diagnostic;
  306. sk->sk_state = TCP_CLOSE;
  307. sk->sk_err = reason;
  308. sk->sk_shutdown |= SEND_SHUTDOWN;
  309. if (!sock_flag(sk, SOCK_DEAD)) {
  310. sk->sk_state_change(sk);
  311. sock_set_flag(sk, SOCK_DEAD);
  312. }
  313. }
  314. /*
  315. * Clear an own-rx-busy condition and tell the peer about this, provided
  316. * that there is a significant amount of free receive buffer space available.
  317. */
  318. void x25_check_rbuf(struct sock *sk)
  319. {
  320. struct x25_sock *x25 = x25_sk(sk);
  321. if (atomic_read(&sk->sk_rmem_alloc) < (sk->sk_rcvbuf / 2) &&
  322. (x25->condition & X25_COND_OWN_RX_BUSY)) {
  323. x25->condition &= ~X25_COND_OWN_RX_BUSY;
  324. x25->condition &= ~X25_COND_ACK_PENDING;
  325. x25->vl = x25->vr;
  326. x25_write_internal(sk, X25_RR);
  327. x25_stop_timer(sk);
  328. }
  329. }