/* * The mrouted program is covered by the license in the accompanying file * named "LICENSE.mrouted". Use of the mrouted program represents acceptance of * the terms and conditions listed in that file. * * The mrouted program is COPYRIGHT 1989 by The Board of Trustees of * Leland Stanford Junior University. * * * inet.c,v 3.8.4.1 1997/01/29 19:49:33 fenner Exp */ #define C(x) ((x) & 0xff) #include "defs.h" /* * Exported variables. */ char s1[MAX_INET_BUF_LEN]; /* buffers to hold the string representations */ char s2[MAX_INET_BUF_LEN]; /* of IP addresses, to be passed to inet_fmt() */ char s3[MAX_INET_BUF_LEN]; char s4[MAX_INET_BUF_LEN]; /* * Verify that a given IP address is credible as a host address. * (Without a mask, cannot detect addresses of the form {subnet,0} or * {subnet,-1}.) */ int inet_valid_host(uint32_t naddr) { uint32_t addr; addr = ntohl(naddr); return !(IN_MULTICAST(addr) || IN_BADCLASS (addr) || (addr & 0xff000000) == 0); } /* * Verify that a given netmask is plausible; * make sure that it is a series of 1's followed by * a series of 0's with no discontiguous 1's. */ int inet_valid_mask(uint32_t mask) { if (~(((mask & -mask) - 1) | mask) != 0) { /* Mask is not contiguous */ return FALSE; } return TRUE; } /* * Verify that a given subnet number and mask pair are credible. * * With CIDR, almost any subnet and mask are credible. mrouted still * can't handle aggregated class A's, so we still check that, but * otherwise the only requirements are that the subnet address is * within the [ABC] range and that the host bits of the subnet * are all 0. */ int inet_valid_subnet(uint32_t nsubnet, uint32_t nmask) { uint32_t subnet, mask; subnet = ntohl(nsubnet); mask = ntohl(nmask); if ((subnet & mask) != subnet) return FALSE; if (subnet == 0) return mask == 0; if (IN_CLASSA(subnet)) { if (mask < 0xff000000 || (subnet & 0xff000000) == 0x7f000000 || (subnet & 0xff000000) == 0x00000000) return FALSE; } else if (IN_CLASSD(subnet) || IN_BADCLASS(subnet)) { /* Above Class C address space */ return FALSE; } if (subnet & ~mask) { /* Host bits are set in the subnet */ return FALSE; } if (!inet_valid_mask(mask)) { /* Netmask is not contiguous */ return FALSE; } return TRUE; } /* * Convert an IP address in uint32_t (network) format into a printable string. */ char *inet_fmt(uint32_t addr, char *s, size_t len) { uint8_t *a; a = (uint8_t *)&addr; snprintf(s, len, "%u.%u.%u.%u", a[0], a[1], a[2], a[3]); return s; } /* * Convert the printable string representation of an IP address into the * uint32_t (network) format. Return 0xffffffff on error. (To detect the * legal address with that value, you must explicitly compare the string * with "255.255.255.255".) * The return value is in network order. */ uint32_t inet_parse(char *s, int n) { uint32_t a = 0; u_int a0 = 0, a1 = 0, a2 = 0, a3 = 0; int i; char c; i = sscanf(s, "%u.%u.%u.%u%c", &a0, &a1, &a2, &a3, &c); if (i < n || i > 4 || a0 > 255 || a1 > 255 || a2 > 255 || a3 > 255) return 0xffffffff; ((uint8_t *)&a)[0] = a0; ((uint8_t *)&a)[1] = a1; ((uint8_t *)&a)[2] = a2; ((uint8_t *)&a)[3] = a3; return a; } /* * inet_cksum extracted from: * P I N G . C * * Author - * Mike Muuss * U. S. Army Ballistic Research Laboratory * December, 1983 * Modified at Uc Berkeley * * (ping.c) Status - * Public Domain. Distribution Unlimited. * * I N _ C K S U M * * Checksum routine for Internet Protocol family headers (C Version) * */ int inet_cksum(uint16_t *addr, u_int len) { int sum = 0; int nleft = (int)len; uint16_t *w = addr; uint16_t answer = 0; /* * Our algorithm is simple, using a 32 bit accumulator (sum), * we add sequential 16 bit words to it, and at the end, fold * back all the carry bits from the top 16 bits into the lower * 16 bits. */ while (nleft > 1) { sum += *w++; nleft -= 2; } /* mop up an odd byte, if necessary */ if (nleft == 1) { *(uint8_t *) (&answer) = *(uint8_t *)w ; sum += answer; } /* * add back carry outs from top 16 bits to low 16 bits */ sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */ sum += (sum >> 16); /* add carry */ answer = ~sum; /* truncate to 16 bits */ return answer; } /* * Called by following netname() to create a mask specified network address. */ void trimdomain(char *cp) { static char domain[MAXHOSTNAMELEN + 1]; static int first = 1; char *s; if (first) { first = 0; if (gethostname(domain, MAXHOSTNAMELEN) == 0 && (s = strchr(domain, '.'))) (void) strlcpy(domain, s + 1, sizeof(domain)); else domain[0] = 0; } if (domain[0]) { while ((cp = strchr(cp, '.'))) { if (!strcasecmp(cp + 1, domain)) { *cp = 0; break; } cp++; } } } static uint32_t forgemask(uint32_t a) { uint32_t m; if (IN_CLASSA(a)) m = IN_CLASSA_NET; else if (IN_CLASSB(a)) m = IN_CLASSB_NET; else m = IN_CLASSC_NET; return (m); } static void domask(char *dst, size_t len, uint32_t addr, uint32_t mask) { int b, i; if (!mask || (forgemask(addr) == mask)) { *dst = '\0'; return; } i = 0; for (b = 0; b < 32; b++) { if (mask & (1 << b)) { int bb; i = b; for (bb = b+1; bb < 32; bb++) { if (!(mask & (1 << bb))) { i = -1; /* noncontig */ break; } } break; } } if (i == -1) snprintf(dst, len, "&0x%x", mask); else snprintf(dst, len, "/%d", 32 - i); } /* * Return the name of the network whose address is given. * The address is assumed to be that of a net or subnet, not a host. */ char *netname(uint32_t addr, uint32_t mask) { static char line[MAXHOSTNAMELEN + 4]; uint32_t omask; uint32_t i; i = ntohl(addr); omask = mask = ntohl(mask); if ((i & 0xffffff) == 0) snprintf(line, sizeof(line), "%u", C(i >> 24)); else if ((i & 0xffff) == 0) snprintf(line, sizeof(line), "%u.%u", C(i >> 24) , C(i >> 16)); else if ((i & 0xff) == 0) snprintf(line, sizeof(line), "%u.%u.%u", C(i >> 24), C(i >> 16), C(i >> 8)); else snprintf(line, sizeof(line), "%u.%u.%u.%u", C(i >> 24), C(i >> 16), C(i >> 8), C(i)); domask(line + strlen(line), sizeof(line) - strlen(line), i, omask); return line; } /** * Local Variables: * version-control: t * indent-tabs-mode: t * c-file-style: "ellemtel" * c-basic-offset: 4 * End: */