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Diffstat (limited to 'usr.sbin/mrouted/inet.c')
| -rw-r--r-- | usr.sbin/mrouted/inet.c | 235 |
1 files changed, 235 insertions, 0 deletions
diff --git a/usr.sbin/mrouted/inet.c b/usr.sbin/mrouted/inet.c new file mode 100644 index 0000000000000..53aad7c63a944 --- /dev/null +++ b/usr.sbin/mrouted/inet.c @@ -0,0 +1,235 @@ +/* + * The mrouted program is covered by the license in the accompanying file + * named "LICENSE". 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 3.8.4.2 1998/01/06 01:57:44 fenner Exp + */ + +#ifndef lint +static const char rcsid[] = + "$FreeBSD$"; +#endif /* not lint */ + +#include "defs.h" + +/* + * Exported variables. + */ +char s1[19]; /* buffers to hold the string representations */ +char s2[19]; /* of IP addresses, to be passed to inet_fmt() */ +char s3[19]; /* or inet_fmts(). */ +char s4[19]; + + +/* + * 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(naddr) + u_int32 naddr; +{ + register u_int32 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(mask) + u_int32 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(nsubnet, nmask) + u_int32 nsubnet, nmask; +{ + register u_int32 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 u_long (network) format into a printable string. + */ +char * +inet_fmt(addr, s) + u_int32 addr; + char *s; +{ + register u_char *a; + + a = (u_char *)&addr; + sprintf(s, "%u.%u.%u.%u", a[0], a[1], a[2], a[3]); + return (s); +} + + +/* + * Convert an IP subnet number in u_long (network) format into a printable + * string including the netmask as a number of bits. + */ +char * +inet_fmts(addr, mask, s) + u_int32 addr, mask; + char *s; +{ + register u_char *a, *m; + int bits; + + if ((addr == 0) && (mask == 0)) { + sprintf(s, "default"); + return (s); + } + a = (u_char *)&addr; + m = (u_char *)&mask; + bits = 33 - ffs(ntohl(mask)); + + if (m[3] != 0) sprintf(s, "%u.%u.%u.%u/%d", a[0], a[1], a[2], a[3], + bits); + else if (m[2] != 0) sprintf(s, "%u.%u.%u/%d", a[0], a[1], a[2], bits); + else if (m[1] != 0) sprintf(s, "%u.%u/%d", a[0], a[1], bits); + else sprintf(s, "%u/%d", a[0], bits); + + return (s); +} + +/* + * Convert the printable string representation of an IP address into the + * u_long (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".) + */ +u_int32 +inet_parse(s,n) + char *s; + int n; +{ + u_int32 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); + + ((u_char *)&a)[0] = a0; + ((u_char *)&a)[1] = a1; + ((u_char *)&a)[2] = a2; + ((u_char *)&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(addr, len) + u_short *addr; + u_int len; +{ + register int nleft = (int)len; + register u_short *w = addr; + u_short answer = 0; + register int sum = 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) { + *(u_char *) (&answer) = *(u_char *)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); +} |