This patch adds a few utility functions to match IP addresses against CIDR masks.
Signed-off-by: Dominik Paulus <dominik.pau...@fau.de> Signed-off-by: Tobias Polzer <tobias.pol...@fau.de> --- drivers/staging/usbip/userspace/src/utils.c | 84 +++++++++++++++++++++++++++++ drivers/staging/usbip/userspace/src/utils.h | 15 ++++++ 2 files changed, 99 insertions(+) diff --git a/drivers/staging/usbip/userspace/src/utils.c b/drivers/staging/usbip/userspace/src/utils.c index 2d4966e..df40817 100644 --- a/drivers/staging/usbip/userspace/src/utils.c +++ b/drivers/staging/usbip/userspace/src/utils.c @@ -74,3 +74,87 @@ int modify_match_busid(char *busid, int add) return ret; } + +/* + * Parses a string of form "ip/prefix" into a subnet mask to dest. + * Returns -1 on error, 0 on success + */ +int parse_cidr(const char *src, struct subnet *dest) +{ + char *ip, *prefix, *saveptr; + char *endptr; + struct in6_addr ip6; + struct in_addr ip4; + int bits; + long int tmp; + char buf[128]; /* For strtok */ + + strncpy(buf, src, sizeof(buf)); + buf[sizeof(buf)-1] = 0; + + ip = strtok_r(buf, "/", &saveptr); + prefix = strtok_r(NULL, "/", &saveptr); + if (strtok_r(NULL, "/", &saveptr) || !ip || + strlen(src) > sizeof(buf) - 1) + return -1; + + if (inet_pton(AF_INET6, ip, &ip6) == 1) { + dest->ai_family = AF_INET6; + bits = 128; + dest->address.ip6 = ip6; + } else if (inet_pton(AF_INET, ip, &ip4) == 1) { + dest->ai_family = AF_INET; + bits = 32; + dest->address.ip4 = ip4; + } else { + return -1; + } + + /* + * We also accept single IPs without an explicitely + * specified prefix + */ + if (prefix) { + tmp = strtol(prefix, &endptr, 10); + if (tmp < 0 || tmp > bits || *endptr != '\0') + return -1; + dest->prefix = tmp; + } else { + dest->prefix = bits; + } + + return 0; +} + +/* + * Checks if addr is in range. Expects addr to be a struct in6_addr* if + * ai_family == AF_INET6, else struct in_addr*. + * Returns 1 if in range, 0 otherwise. + */ +int in_range(struct sockaddr_storage *addr, struct subnet range) +{ + if (addr->ss_family != range.ai_family) + return 0; + if (addr->ss_family == AF_INET6) { + int i; + struct sockaddr_in6 *in6addr = (struct sockaddr_in6 *) addr; + unsigned char *ip = in6addr->sin6_addr.s6_addr; + for (i = 0; i < range.prefix; ++i) { + int idx = i/8, mask = 1 << (7 - i%8); + if ((ip[idx] & mask) != (range.address.ip6.s6_addr[idx] + & mask)) + return 0; + } + } else { + int i; + struct sockaddr_in *inaddr = (struct sockaddr_in *) addr; + uint32_t ip = ntohl(inaddr->sin_addr.s_addr); + uint32_t comp = ntohl(range.address.ip4.s_addr); + for (i = 0; i < range.prefix; ++i) { + int mask = 1 << (31-i); + if ((ip & mask) != (comp & mask)) + return 0; + } + } + return 1; +} diff --git a/drivers/staging/usbip/userspace/src/utils.h b/drivers/staging/usbip/userspace/src/utils.h index 5916fd3..a3704ef 100644 --- a/drivers/staging/usbip/userspace/src/utils.h +++ b/drivers/staging/usbip/userspace/src/utils.h @@ -19,7 +19,22 @@ #ifndef __UTILS_H #define __UTILS_H +#include <arpa/inet.h> +#include <sys/socket.h> +#include <netinet/ip.h> + +struct subnet { + int ai_family; + int prefix; + union { + struct in6_addr ip6; + struct in_addr ip4; + } address; +}; + int modify_match_busid(char *busid, int add); +int parse_cidr(const char *src, struct subnet *dest); +int in_range(struct sockaddr_storage *addr, struct subnet range); #endif /* __UTILS_H */ -- 1.8.4.1 _______________________________________________ devel mailing list de...@linuxdriverproject.org http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel