diff options
| author | Denis Ovsienko <infrastation@yandex.ru> | 2011-10-08 18:15:21 +0400 |
|---|---|---|
| committer | Denis Ovsienko <infrastation@yandex.ru> | 2011-10-17 18:47:38 +0400 |
| commit | cc6647f230a55f1f4fd765a2012561047d9ae6d1 (patch) | |
| tree | 3031ae0a96698fa3cc183bcec5256686ddeceb79 /lib | |
| parent | 484af2c2e0efe660e00e27647a19f1837a7fa437 (diff) | |
lib: make masklen2ip() safer and faster
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/prefix.c | 55 | ||||
| -rw-r--r-- | lib/prefix.h | 2 |
2 files changed, 40 insertions, 17 deletions
diff --git a/lib/prefix.c b/lib/prefix.c index 61a278ca..ff8abd1b 100644 --- a/lib/prefix.c +++ b/lib/prefix.c @@ -31,6 +31,42 @@ /* Maskbit. */ static const u_char maskbit[] = {0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe, 0xff}; +static const u_int32_t maskbytes[] = +{ + 0x00000000, /* /0 0.0.0.0 */ + 0x80000000, /* /1 128.0.0.0 */ + 0xc0000000, /* /2 192.0.0.0 */ + 0xe0000000, /* /3 224.0.0.0 */ + 0xf0000000, /* /4 240.0.0.0 */ + 0xf8000000, /* /5 248.0.0.0 */ + 0xfc000000, /* /6 252.0.0.0 */ + 0xfe000000, /* /7 254.0.0.0 */ + 0xff000000, /* /8 255.0.0.0 */ + 0xff800000, /* /9 255.128.0.0 */ + 0xffc00000, /* /10 255.192.0.0 */ + 0xffe00000, /* /11 255.224.0.0 */ + 0xfff00000, /* /12 255.240.0.0 */ + 0xfff80000, /* /13 255.248.0.0 */ + 0xfffc0000, /* /14 255.252.0.0 */ + 0xfffe0000, /* /15 255.254.0.0 */ + 0xffff0000, /* /16 255.255.0.0 */ + 0xffff8000, /* /17 255.255.128.0 */ + 0xffffc000, /* /18 255.255.192.0 */ + 0xffffe000, /* /19 255.255.224.0 */ + 0xfffff000, /* /20 255.255.240.0 */ + 0xfffff800, /* /21 255.255.248.0 */ + 0xfffffc00, /* /22 255.255.252.0 */ + 0xfffffe00, /* /23 255.255.254.0 */ + 0xffffff00, /* /24 255.255.255.0 */ + 0xffffff80, /* /25 255.255.255.128 */ + 0xffffffc0, /* /26 255.255.255.192 */ + 0xffffffe0, /* /27 255.255.255.224 */ + 0xfffffff0, /* /28 255.255.255.240 */ + 0xfffffff8, /* /29 255.255.255.248 */ + 0xfffffffc, /* /30 255.255.255.252 */ + 0xfffffffe, /* /31 255.255.255.254 */ + 0xffffffff /* /32 255.255.255.255 */ +}; /* Number of bits in prefix type. */ #ifndef PNBBY @@ -263,23 +299,10 @@ str2prefix_ipv4 (const char *str, struct prefix_ipv4 *p) /* Convert masklen into IP address's netmask. */ void -masklen2ip (int masklen, struct in_addr *netmask) +masklen2ip (const int masklen, struct in_addr *netmask) { - u_char *pnt; - int bit; - int offset; - - memset (netmask, 0, sizeof (struct in_addr)); - pnt = (unsigned char *) netmask; - - offset = masklen / 8; - bit = masklen % 8; - - while (offset--) - *pnt++ = 0xff; - - if (bit) - *pnt = maskbit[bit]; + assert (masklen >= 0 && masklen <= 32); + netmask->s_addr = maskbytes[masklen]; } /* Convert IP address's netmask into integer. We assume netmask is diff --git a/lib/prefix.h b/lib/prefix.h index 1cb91b2a..42334649 100644 --- a/lib/prefix.h +++ b/lib/prefix.h @@ -176,7 +176,7 @@ extern int prefix_ipv4_any (const struct prefix_ipv4 *); extern void apply_classful_mask_ipv4 (struct prefix_ipv4 *); extern u_char ip_masklen (struct in_addr); -extern void masklen2ip (int, struct in_addr *); +extern void masklen2ip (const int, struct in_addr *); /* returns the network portion of the host address */ extern in_addr_t ipv4_network_addr (in_addr_t hostaddr, int masklen); /* given the address of a host on a network and the network mask length, |