/contrib/ntp/libntp/netof.c

https://bitbucket.org/freebsd/freebsd-head/ · C · 48 lines · 31 code · 7 blank · 10 comment · 10 complexity · ff7aab6a269406e0197662693ff4c2f2 MD5 · raw file

  1. /*
  2. * netof - return the net address part of an ip address in a sockaddr_storage structure
  3. * (zero out host part)
  4. */
  5. #include <stdio.h>
  6. #include "ntp_fp.h"
  7. #include "ntp_stdlib.h"
  8. #include "ntp.h"
  9. #define NUM_NETOF_BUFS 10
  10. static struct sockaddr_storage ssbuf[NUM_NETOF_BUFS];
  11. static int next_ssbuf = 0;
  12. struct sockaddr_storage*
  13. netof(
  14. struct sockaddr_storage* hostaddr
  15. )
  16. {
  17. register u_int32 netnum;
  18. struct sockaddr_storage *netaddr;
  19. netaddr = &ssbuf[next_ssbuf++];
  20. if (next_ssbuf == NUM_NETOF_BUFS)
  21. next_ssbuf = 0;
  22. memcpy(netaddr, hostaddr, sizeof(struct sockaddr_storage));
  23. if(netaddr->ss_family == AF_INET) {
  24. netnum = ((struct sockaddr_in*)netaddr)->sin_addr.s_addr;
  25. /*
  26. * We live in a modern CIDR world where the basement nets, which
  27. * used to be class A, are now probably associated with each
  28. * host address. So, for class-A nets, all bits are significant.
  29. */
  30. if(IN_CLASSC(netnum))
  31. netnum &= IN_CLASSC_NET;
  32. else if (IN_CLASSB(netnum))
  33. netnum &= IN_CLASSB_NET;
  34. ((struct sockaddr_in*)netaddr)->sin_addr.s_addr = netnum;
  35. }
  36. else if(netaddr->ss_family == AF_INET6) {
  37. /* Here we put 0 at the local link address so we get net address */
  38. memset(&((struct sockaddr_in6*)netaddr)->sin6_addr.s6_addr[8], 0, 8*sizeof(u_char));
  39. }
  40. return netaddr;
  41. }