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
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