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icmp_in.c
Package: icmp.rar　[view]
Upload User: lywr2008
Upload Date: 2022-05-26
Package Size: 9k
Code Size: 2k
Category:

Linux Network

Development Platform:

Unix_Linux

icmp_in.c：Code Content
  1. /* icmp_in.c - icmp_in */
  3. #include <conf.h>
  4. #include <kernel.h>
  5. #include <network.h>
  6. #include <proc.h>
  8. int icredirect(struct ep *);
  9. void icsetsrc(struct ip *);
  11. /*------------------------------------------------------------------------
  12.  *  icmp_in  -  handle ICMP packet coming in from the network
  13.  *------------------------------------------------------------------------
  14.  */
  15. int
  16. icmp_in(struct netif *pni, struct ep *pep)
  17. {
  18. struct ip *pip;
  19. struct icmp *pic;
  20. int i, len;
  22. pip = (struct ip *)pep->ep_data;
  23. pic = (struct icmp *) pip->ip_data;
  25. len = pip->ip_len - IP_HLEN(pip);
  26. if (cksum((WORD *)pic, len)) {
  27. IcmpInErrors++;
  28. freebuf(pep);
  29. return SYSERR;
  30. }
  31. IcmpInMsgs++;
  32. switch(pic->ic_type) {
  33. case ICT_ECHORQ:
  34. IcmpInEchos++;
  35. return icmp(ICT_ECHORP, 0, pip->ip_src, pep, 0);
  36. case ICT_MASKRQ:
  37. IcmpInAddrMasks++;
  38. if (!gateway) {
  39. freebuf(pep);
  40. return OK;
  41. }
  42. pic->ic_type = (char) ICT_MASKRP;
  43. *(IPaddr *)pic->ic_data = netmask(pip->ip_dst);
  44. break;
  45. case ICT_MASKRP:
  46. IcmpInAddrMaskReps++;
  47. for (i=0; i<Net.nif; ++i)
  48. if (nif[i].ni_ip == pip->ip_dst)
  49. break;
  50. if (i != Net.nif) {
  51. setmask(i, *(IPaddr *)pic->ic_data);
  52. send(pic->ic_id, ICT_MASKRP);
  53. }
  54. freebuf(pep);
  55. return OK;
  56. case ICT_ECHORP:
  57. IcmpInEchoReps++;
  58. if (send(pic->ic_id, (int)pep) != OK)
  59. freebuf(pep);
  60. return OK;
  61. case ICT_REDIRECT:
  62. IcmpInRedirects++;
  63. icredirect(pep);
  64. return OK;
  65. case ICT_DESTUR: IcmpInDestUnreachs++; freebuf(pep); return OK;
  66. case ICT_SRCQ:  IcmpInSrcQuenchs++; freebuf(pep); return OK;
  67. case ICT_TIMEX:  IcmpInTimeExcds++; freebuf(pep); return OK;
  68. case ICT_PARAMP: IcmpInParmProbs++; freebuf(pep); return OK;
  69. case ICT_TIMERQ: IcmpInTimestamps++; freebuf(pep); return OK;
  70. case ICT_TIMERP: IcmpInTimestampReps++; freebuf(pep); return OK;
  71. default:
  72. IcmpInErrors++;
  73. freebuf(pep);
  74. return OK;
  75. }
  76. icsetsrc(pip);
  78. len = pip->ip_len - IP_HLEN(pip);
  80. pic->ic_cksum = 0;
  81. pic->ic_cksum = cksum((WORD *)pic, len);
  83. IcmpOutMsgs++;
  84. ipsend(pip->ip_dst, pep, len, IPT_ICMP, IPP_INCTL, IP_TTL);
  85. return OK;
  86. }