d867f32a7
Denis Vlasenko
2007-08-19
Subject
httpd: explain IP/mask parsing, and simplify it a bit.
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networking/httpd.c+48 -33
| @@ -289,17 +289,26 @@ static ALWAYS_INLINE void free_Htaccess_IP_list(Htaccess_IP **pptr) | |
| free_llist((has_next_ptr**)pptr); | |
| } | |
| - | static int scan_ip(const char **ep, unsigned *ip, unsigned char endc) |
| + | //#undef isdigit |
| + | //#define isdigit(a) ((unsigned)((a) - '0') <= 9) |
| + | //#define notdigit(a) ((unsigned)((a) - '0') > 9) |
| + | |
| + | /* Returns presumed mask width in bits or < 0 on error. |
| + | * Updates strp, stores IP at provided pointer */ |
| + | static int scan_ip(const char **strp, unsigned *ipp, unsigned char endc) |
| { | |
| - | const char *p = *ep; |
| + | const char *p = *strp; |
| int auto_mask = 8; | |
| + | unsigned ip = 0; |
| int j; | |
| - | *ip = 0; |
| + | if (*p == '/') |
| + | return -auto_mask; |
| + | |
| for (j = 0; j < 4; j++) { | |
| unsigned octet; | |
| - | if ((*p < '0' || *p > '9') && (*p != '/' || j == 0) && *p != '\0') |
| + | if ((*p < '0' || *p > '9') && *p != '/' && *p) |
| return -auto_mask; | |
| octet = 0; | |
| while (*p >= '0' && *p <= '9') { | |
| @@ -311,55 +320,61 @@ static int scan_ip(const char **ep, unsigned *ip, unsigned char endc) | |
| } | |
| if (*p == '.') | |
| p++; | |
| - | if (*p != '/' && *p != '\0') |
| + | if (*p != '/' && *p) |
| auto_mask += 8; | |
| - | *ip = ((*ip) << 8) | octet; |
| + | ip = (ip << 8) | octet; |
| } | |
| - | if (*p != '\0') { |
| + | if (*p) { |
| if (*p != endc) | |
| return -auto_mask; | |
| p++; | |
| if (*p == '\0') | |
| return -auto_mask; | |
| } | |
| - | *ep = p; |
| + | *ipp = ip; |
| + | *strp = p; |
| return auto_mask; | |
| } | |
| - | static int scan_ip_mask(const char *ipm, unsigned *ip, unsigned *mask) |
| + | /* Returns 0 on success. Stores IP and mask at provided pointers */ |
| + | static int scan_ip_mask(const char *str, unsigned *ipp, unsigned *maskp) |
| { | |
| int i; | |
| - | unsigned msk; |
| + | unsigned mask; |
| + | char *p; |
| - | i = scan_ip(&ipm, ip, '/'); |
| + | i = scan_ip(&str, ipp, '/'); |
| if (i < 0) | |
| return i; | |
| - | if (*ipm) { |
| - | const char *p = ipm; |
| - | |
| - | i = 0; |
| - | while (*p) { |
| - | if (*p < '0' || *p > '9') { |
| - | if (*p == '.') { |
| - | i = scan_ip(&ipm, mask, 0); |
| - | return i != 32; |
| - | } |
| - | return -1; |
| - | } |
| - | i *= 10; |
| - | i += *p - '0'; |
| - | p++; |
| + | |
| + | if (*str) { |
| + | /* there is /xxx after dotted-IP address */ |
| + | i = bb_strtou(str, &p, 10); |
| + | if (*p == '.') { |
| + | /* 'xxx' itself is dotted-IP mask, parse it */ |
| + | /* (return 0 (success) only if it has N.N.N.N form) */ |
| + | return scan_ip(&str, maskp, '\0') - 32; |
| } | |
| + | if (*p) |
| + | return -1; |
| } | |
| - | if (i > 32 || i < 0) |
| + | |
| + | if (i > 32) |
| return -1; | |
| - | msk = 0x80000000; |
| - | *mask = 0; |
| - | while (i > 0) { |
| - | *mask |= msk; |
| - | msk >>= 1; |
| - | i--; |
| + | |
| + | if (sizeof(unsigned) == 4 && i == 32) { |
| + | /* mask >>= 32 below may not work */ |
| + | mask = 0; |
| + | } else { |
| + | mask = 0xffffffff; |
| + | mask >>= i; |
| } | |
| + | /* i == 0 -> *maskp = 0x00000000 |
| + | * i == 1 -> *maskp = 0x80000000 |
| + | * i == 4 -> *maskp = 0xf0000000 |
| + | * i == 31 -> *maskp = 0xfffffffe |
| + | * i == 32 -> *maskp = 0xffffffff */ |
| + | *maskp = (uint32_t)(~mask); |
| return 0; | |
| } | |