1 files changed, 136 insertions, 115 deletions

diff --git a/libnetutils/ifc_utils.c b/libnetutils/ifc_utils.c
index 0ca5fe6..c9d6ed2 100644
--- a/libnetutils/ifc_utils.c
+++ b/libnetutils/ifc_utils.c
@@ -25,6 +25,7 @@
 #include <sys/types.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
+#include <net/if.h>
 
 #include <linux/if.h>
 #include <linux/if_ether.h>
@@ -50,6 +51,33 @@ static int ifc_ctl_sock = -1;
 static int ifc_ctl_sock6 = -1;
 void printerr(char *fmt, ...);
 
+in_addr_t prefixLengthToIpv4Netmask(int prefix_length)
+{
+    in_addr_t mask = 0;
+
+    // C99 (6.5.7): shifts of 32 bits have undefined results
+    if (prefix_length <= 0 || prefix_length > 32) {
+        return 0;
+    }
+
+    mask = ~mask << (32 - prefix_length);
+    mask = htonl(mask);
+
+    return mask;
+}
+
+int ipv4NetmaskToPrefixLength(in_addr_t mask)
+{
+    mask = ntohl(mask);
+    int prefixLength = 0;
+    uint32_t m = (uint32_t)mask;
+    while (m & 0x80000000) {
+        prefixLength++;
+        m = m << 1;
+    }
+    return prefixLength;
+}
+
 static const char *ipaddr_to_string(in_addr_t addr)
 {
     struct in_addr in_addr;
@@ -126,7 +154,7 @@ int ifc_get_ifindex(const char *name, int *if_indexp)
     if(r < 0) return -1;
 
     *if_indexp = ifr.ifr_ifindex;
-    return 0;    
+    return 0;
 }
 
 static int ifc_set_flags(const char *name, unsigned set, unsigned clr)
@@ -163,7 +191,7 @@ int ifc_set_addr(const char *name, in_addr_t addr)
 
     ifc_init_ifr(name, &ifr);
     init_sockaddr_in(&ifr.ifr_addr, addr);
-    
+
     return ioctl(ifc_ctl_sock, SIOCSIFADDR, &ifr);
 }
 
@@ -178,17 +206,37 @@ int ifc_set_hwaddr(const char *name, const void *ptr)
     return ioctl(ifc_ctl_sock, SIOCSIFHWADDR, &ifr);
 }
 
-int ifc_set_mask(const char *name, in_addr_t mask)
+int ifc_set_prefixLength(const char *name, int prefixLength)
 {
     struct ifreq ifr;
+    // TODO - support ipv6
+    if (prefixLength > 32 || prefixLength < 0) return -1;
 
+    in_addr_t mask = prefixLengthToIpv4Netmask(prefixLength);
     ifc_init_ifr(name, &ifr);
     init_sockaddr_in(&ifr.ifr_addr, mask);
-    
+
     return ioctl(ifc_ctl_sock, SIOCSIFNETMASK, &ifr);
 }
 
-int ifc_get_info(const char *name, in_addr_t *addr, in_addr_t *mask, unsigned *flags)
+int ifc_get_addr(const char *name, in_addr_t *addr)
+{
+    struct ifreq ifr;
+    int ret = 0;
+
+    ifc_init_ifr(name, &ifr);
+    if (addr != NULL) {
+        ret = ioctl(ifc_ctl_sock, SIOCGIFADDR, &ifr);
+        if (ret < 0) {
+            *addr = 0;
+        } else {
+            *addr = ((struct sockaddr_in*) &ifr.ifr_addr)->sin_addr.s_addr;
+        }
+    }
+    return ret;
+}
+
+int ifc_get_info(const char *name, in_addr_t *addr, int *prefixLength, unsigned *flags)
 {
     struct ifreq ifr;
     ifc_init_ifr(name, &ifr);
@@ -200,12 +248,13 @@ int ifc_get_info(const char *name, in_addr_t *addr, in_addr_t *mask, unsigned *f
             *addr = ((struct sockaddr_in*) &ifr.ifr_addr)->sin_addr.s_addr;
         }
     }
-    
-    if (mask != NULL) {
+
+    if (prefixLength != NULL) {
         if(ioctl(ifc_ctl_sock, SIOCGIFNETMASK, &ifr) < 0) {
-            *mask = 0;
+            *prefixLength = 0;
         } else {
-            *mask = ((struct sockaddr_in*) &ifr.ifr_addr)->sin_addr.s_addr;
+            *prefixLength = ipv4NetmaskToPrefixLength((int)
+                    ((struct sockaddr_in*) &ifr.ifr_addr)->sin_addr.s_addr);
         }
     }
 
@@ -220,17 +269,7 @@ int ifc_get_info(const char *name, in_addr_t *addr, in_addr_t *mask, unsigned *f
     return 0;
 }
 
-in_addr_t get_ipv4_netmask(int prefix_length)
-{
-    in_addr_t mask = 0;
-
-    mask = ~mask << (32 - prefix_length);
-    mask = htonl(mask);
-
-    return mask;
-}
-
-int ifc_add_ipv4_route(const char *ifname, struct in_addr dst, int prefix_length,
+int ifc_act_on_ipv4_route(int action, const char *ifname, struct in_addr dst, int prefix_length,
       struct in_addr gw)
 {
     struct rtentry rt;
@@ -242,7 +281,7 @@ int ifc_add_ipv4_route(const char *ifname, struct in_addr dst, int prefix_length
     rt.rt_dst.sa_family = AF_INET;
     rt.rt_dev = (void*) ifname;
 
-    netmask = get_ipv4_netmask(prefix_length);
+    netmask = prefixLengthToIpv4Netmask(prefix_length);
     init_sockaddr_in(&rt.rt_genmask, netmask);
     init_sockaddr_in(&rt.rt_dst, dst.s_addr);
     rt.rt_flags = RTF_UP;
@@ -262,7 +301,7 @@ int ifc_add_ipv4_route(const char *ifname, struct in_addr dst, int prefix_length
         return -errno;
     }
 
-    result = ioctl(ifc_ctl_sock, SIOCADDRT, &rt);
+    result = ioctl(ifc_ctl_sock, action, &rt);
     if (result < 0) {
         if (errno == EEXIST) {
             result = 0;
@@ -281,17 +320,7 @@ int ifc_create_default_route(const char *name, in_addr_t gw)
     in_dst.s_addr = 0;
     in_gw.s_addr = gw;
 
-    return ifc_add_ipv4_route(name, in_dst, 0, in_gw);
-}
-
-int ifc_add_host_route(const char *name, in_addr_t dst)
-{
-    struct in_addr in_dst, in_gw;
-
-    in_dst.s_addr = dst;
-    in_gw.s_addr = 0;
-
-    return ifc_add_ipv4_route(name, in_dst, 32, in_gw);
+    return ifc_act_on_route(SIOCADDRT, name, in_dst, 0, in_gw);
 }
 
 int ifc_enable(const char *ifname)
@@ -306,29 +335,65 @@ int ifc_enable(const char *ifname)
 
 int ifc_disable(const char *ifname)
 {
+    unsigned addr, count;
     int result;
 
     ifc_init();
     result = ifc_down(ifname);
+
     ifc_set_addr(ifname, 0);
+    for (count=0, addr=1;((addr != 0) && (count < 255)); count++) {
+       if (ifc_get_addr(ifname, &addr) < 0)
+            break;
+       if (addr)
+          ifc_set_addr(ifname, 0);
+    }
+
     ifc_close();
     return result;
 }
 
-int ifc_reset_connections(const char *ifname)
+#define RESET_IPV4_ADDRESSES 0x01
+#define RESET_IPV6_ADDRESSES 0x02
+#define RESET_ALL_ADDRESSES  (RESET_IPV4_ADDRESSES | RESET_IPV6_ADDRESSES)
+
+int ifc_reset_connections(const char *ifname, const int reset_mask)
 {
 #ifdef HAVE_ANDROID_OS
-    int result;
+    int result, success;
     in_addr_t myaddr;
     struct ifreq ifr;
+    struct in6_ifreq ifr6;
+
+    if (reset_mask & RESET_IPV4_ADDRESSES) {
+        /* IPv4. Clear connections on the IP address. */
+        ifc_init();
+        ifc_get_info(ifname, &myaddr, NULL, NULL);
+        ifc_init_ifr(ifname, &ifr);
+        init_sockaddr_in(&ifr.ifr_addr, myaddr);
+        result = ioctl(ifc_ctl_sock, SIOCKILLADDR,  &ifr);
+        ifc_close();
+    } else {
+        result = 0;
+    }
+
+    if (reset_mask & RESET_IPV6_ADDRESSES) {
+        /*
+         * IPv6. On Linux, when an interface goes down it loses all its IPv6
+         * addresses, so we don't know which connections belonged to that interface
+         * So we clear all unused IPv6 connections on the device by specifying an
+         * empty IPv6 address.
+         */
+        ifc_init6();
+        // This implicitly specifies an address of ::, i.e., kill all IPv6 sockets.
+        memset(&ifr6, 0, sizeof(ifr6));
+        success = ioctl(ifc_ctl_sock6, SIOCKILLADDR,  &ifr6);
+        if (result == 0) {
+            result = success;
+        }
+        ifc_close6();
+    }
 
-    ifc_init();
-    ifc_get_info(ifname, &myaddr, NULL, NULL);
-    ifc_init_ifr(ifname, &ifr);
-    init_sockaddr_in(&ifr.ifr_addr, myaddr);
-    result = ioctl(ifc_ctl_sock, SIOCKILLADDR,  &ifr);
-    ifc_close();
-    
     return result;
 #else
     return 0;
@@ -384,67 +449,6 @@ int ifc_remove_host_routes(const char *name)
 }
 
 /*
- * Return the address of the default gateway
- *
- * TODO: factor out common code from this and remove_host_routes()
- * so that we only scan /proc/net/route in one place.
- */
-int ifc_get_default_route(const char *ifname)
-{
-    char name[64];
-    in_addr_t dest, gway, mask;
-    int flags, refcnt, use, metric, mtu, win, irtt;
-    int result;
-    FILE *fp;
-
-    fp = fopen("/proc/net/route", "r");
-    if (fp == NULL)
-        return 0;
-    /* Skip the header line */
-    if (fscanf(fp, "%*[^\n]\n") < 0) {
-        fclose(fp);
-        return 0;
-    }
-    ifc_init();
-    result = 0;
-    for (;;) {
-        int nread = fscanf(fp, "%63s%X%X%X%d%d%d%X%d%d%d\n",
-                           name, &dest, &gway, &flags, &refcnt, &use, &metric, &mask,
-                           &mtu, &win, &irtt);
-        if (nread != 11) {
-            break;
-        }
-        if ((flags & (RTF_UP|RTF_GATEWAY)) == (RTF_UP|RTF_GATEWAY)
-                && dest == 0
-                && strcmp(ifname, name) == 0) {
-            result = gway;
-            break;
-        }
-    }
-    fclose(fp);
-    ifc_close();
-    return result;
-}
-
-/*
- * Sets the specified gateway as the default route for the named interface.
- */
-int ifc_set_default_route(const char *ifname, in_addr_t gateway)
-{
-    struct in_addr addr;
-    int result;
-
-    ifc_init();
-    addr.s_addr = gateway;
-    if ((result = ifc_create_default_route(ifname, gateway)) < 0) {
-        LOGD("failed to add %s as default route for %s: %s",
-             inet_ntoa(addr), ifname, strerror(errno));
-    }
-    ifc_close();
-    return result;
-}
-
-/*
  * Removes the default route for the named interface.
  */
 int ifc_remove_default_route(const char *ifname)
@@ -467,7 +471,7 @@ int ifc_remove_default_route(const char *ifname)
 int
 ifc_configure(const char *ifname,
         in_addr_t address,
-        in_addr_t netmask,
+        uint32_t prefixLength,
         in_addr_t gateway,
         in_addr_t dns1,
         in_addr_t dns2) {
@@ -486,8 +490,8 @@ ifc_configure(const char *ifname,
         ifc_close();
         return -1;
     }
-    if (ifc_set_mask(ifname, netmask)) {
-        printerr("failed to set netmask %s: %s\n", ipaddr_to_string(netmask), strerror(errno));
+    if (ifc_set_prefixLength(ifname, prefixLength)) {
+        printerr("failed to set prefixLength %d: %s\n", prefixLength, strerror(errno));
         ifc_close();
         return -1;
     }
@@ -507,7 +511,7 @@ ifc_configure(const char *ifname,
     return 0;
 }
 
-int ifc_add_ipv6_route(const char *ifname, struct in6_addr dst, int prefix_length,
+int ifc_act_on_ipv6_route(int action, const char *ifname, struct in6_addr dst, int prefix_length,
       struct in6_addr gw)
 {
     struct in6_rtmsg rtmsg;
@@ -542,7 +546,7 @@ int ifc_add_ipv6_route(const char *ifname, struct in6_addr dst, int prefix_lengt
         return -errno;
     }
 
-    result = ioctl(ifc_ctl_sock6, SIOCADDRT, &rtmsg);
+    result = ioctl(ifc_ctl_sock6, action, &rtmsg);
     if (result < 0) {
         if (errno == EEXIST) {
             result = 0;
@@ -554,8 +558,8 @@ int ifc_add_ipv6_route(const char *ifname, struct in6_addr dst, int prefix_lengt
     return result;
 }
 
-int ifc_add_route(const char *ifname, const char *dst, int prefix_length,
-      const char *gw)
+int ifc_act_on_route(int action, const char *ifname, const char *dst, int prefix_length,
+        const char *gw)
 {
     int ret = 0;
     struct sockaddr_in ipv4_dst, ipv4_gw;
@@ -573,7 +577,7 @@ int ifc_add_route(const char *ifname, const char *dst, int prefix_length,
         return -EINVAL;
     }
 
-    if (gw == NULL) {
+    if (gw == NULL || (strlen(gw) == 0)) {
         if (addr_ai->ai_family == AF_INET6) {
             gw = "::";
         } else if (addr_ai->ai_family == AF_INET) {
@@ -581,6 +585,13 @@ int ifc_add_route(const char *ifname, const char *dst, int prefix_length,
         }
     }
 
+    if (((addr_ai->ai_family == AF_INET6) && (prefix_length < 0 || prefix_length > 128)) ||
+            ((addr_ai->ai_family == AF_INET) && (prefix_length < 0 || prefix_length > 32))) {
+        printerr("ifc_add_route: invalid prefix length");
+        freeaddrinfo(addr_ai);
+        return -EINVAL;
+    }
+
     ret = getaddrinfo(gw, NULL, &hints, &gw_ai);
     if (ret != 0) {
         printerr("getaddrinfo failed: invalid gateway %s\n", gw);
@@ -598,13 +609,13 @@ int ifc_add_route(const char *ifname, const char *dst, int prefix_length,
     if (addr_ai->ai_family == AF_INET6) {
         memcpy(&ipv6_dst, addr_ai->ai_addr, sizeof(struct sockaddr_in6));
         memcpy(&ipv6_gw, gw_ai->ai_addr, sizeof(struct sockaddr_in6));
-        ret = ifc_add_ipv6_route(ifname, ipv6_dst.sin6_addr, prefix_length,
-              ipv6_gw.sin6_addr);
+        ret = ifc_act_on_ipv6_route(action, ifname, ipv6_dst.sin6_addr,
+                prefix_length, ipv6_gw.sin6_addr);
     } else if (addr_ai->ai_family == AF_INET) {
         memcpy(&ipv4_dst, addr_ai->ai_addr, sizeof(struct sockaddr_in));
         memcpy(&ipv4_gw, gw_ai->ai_addr, sizeof(struct sockaddr_in));
-        ret = ifc_add_ipv4_route(ifname, ipv4_dst.sin_addr, prefix_length,
-              ipv4_gw.sin_addr);
+        ret = ifc_act_on_ipv4_route(action, ifname, ipv4_dst.sin_addr,
+                prefix_length, ipv4_gw.sin_addr);
     } else {
         printerr("ifc_add_route: getaddrinfo returned un supported address family %d\n",
                   addr_ai->ai_family);
@@ -615,3 +626,13 @@ int ifc_add_route(const char *ifname, const char *dst, int prefix_length,
     freeaddrinfo(gw_ai);
     return ret;
 }
+
+int ifc_add_route(const char *ifname, const char *dst, int prefix_length, const char *gw)
+{
+    return ifc_act_on_route(SIOCADDRT, ifname, dst, prefix_length, gw);
+}
+
+int ifc_remove_route(const char *ifname, const char*dst, int prefix_length, const char *gw)
+{
+    return ifc_act_on_route(SIOCDELRT, ifname, dst, prefix_length, gw);
+}