dhcpcd-6.8.2: add ifaddrs.c and ifaddrs.h

Add an Android implementation of ifaddrs to the
dhcpcd-6.8.2 repo, which this daemon depends on.

ifaddr.c cherry-picked from
https://googleplex-android.git.corp.google.com/platform/external/dhcpcd/+/master
at 31db56e5b40726fed587656ac1730705c79741b9.

ifaddr.h cherry-picked from
https://googleplex-android.git.corp.google.com/platform/external/dhcpcd/+/master
at e86eee143ed21592f88a46623a81f71002430459.

BUG: 22956197
Change-Id: Id19c9ee8e7c0c32b36742052f9ee63dc197aa218

2 files changed, 183 insertions, 0 deletions

diff --git a/ifaddrs.c b/ifaddrs.c
new file mode 100644
index 0000000..a88bcc1
--- /dev/null
+++ b/ifaddrs.c
@@ -0,0 +1,149 @@
+/* external/dhcpcd-6.8.2/ifaddrs.c
+** Copied from external/dhcpcd/ifaddrs.c.
+**
+** Copyright 2011, The Android Open Source Project
+**
+** Licensed under the Apache License, Version 2.0 (the "License");.
+** you may not use this file except in compliance with the License..
+** You may obtain a copy of the License at.
+**
+**     http://www.apache.org/licenses/LICENSE-2.0.
+**
+** Unless required by applicable law or agreed to in writing, software.
+** distributed under the License is distributed on an "AS IS" BASIS,.
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied..
+** See the License for the specific language governing permissions and.
+** limitations under the License.
+*/
+
+#include <arpa/inet.h>
+#include <sys/socket.h>
+#include "ifaddrs.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <dirent.h>
+#include <netinet/ether.h>
+#include <netdb.h>
+#include <linux/if_packet.h>
+#include <netinet/if_ether.h>
+#include <linux/if_arp.h>
+#include <netutils/ifc.h>
+
+struct ifaddrs *get_interface(const char *name, sa_family_t family)
+{
+    unsigned addr, flags;
+    int masklen;
+    struct ifaddrs *ifa;
+    struct sockaddr_in *saddr = NULL;
+    struct sockaddr_in *smask = NULL;
+    struct sockaddr_ll *hwaddr = NULL;
+    unsigned char hwbuf[ETH_ALEN];
+
+    if (ifc_get_info(name, &addr, &masklen, &flags))
+        return NULL;
+
+    if ((family == AF_INET) && (addr == 0))
+        return NULL;
+
+    ifa = malloc(sizeof(struct ifaddrs));
+    if (!ifa)
+        return NULL;
+    memset(ifa, 0, sizeof(struct ifaddrs));
+
+    ifa->ifa_name = malloc(strlen(name)+1);
+    if (!ifa->ifa_name) {
+        free(ifa);
+        return NULL;
+    }
+    strcpy(ifa->ifa_name, name);
+    ifa->ifa_flags = flags;
+
+    if (family == AF_INET) {
+        saddr = malloc(sizeof(struct sockaddr_in));
+        if (saddr) {
+            saddr->sin_addr.s_addr = addr;
+            saddr->sin_family = family;
+        }
+        ifa->ifa_addr = (struct sockaddr *)saddr;
+
+        if (masklen != 0) {
+            smask = malloc(sizeof(struct sockaddr_in));
+            if (smask) {
+                smask->sin_addr.s_addr = prefixLengthToIpv4Netmask(masklen);
+                smask->sin_family = family;
+            }
+        }
+        ifa->ifa_netmask = (struct sockaddr *)smask;
+    } else if (family == AF_PACKET) {
+        if (!ifc_get_hwaddr(name, hwbuf)) {
+            hwaddr = malloc(sizeof(struct sockaddr_ll));
+            if (hwaddr) {
+                memset(hwaddr, 0, sizeof(struct sockaddr_ll));
+                hwaddr->sll_family = family;
+                /* hwaddr->sll_protocol = ETHERTYPE_IP; */
+                hwaddr->sll_hatype = ARPHRD_ETHER;
+                hwaddr->sll_halen = ETH_ALEN;
+                memcpy(hwaddr->sll_addr, hwbuf, ETH_ALEN);
+            }
+        }
+        ifa->ifa_addr = (struct sockaddr *)hwaddr;
+        ifa->ifa_netmask = (struct sockaddr *)smask;
+    }
+    return ifa;
+}
+
+int getifaddrs(struct ifaddrs **ifap)
+{
+    DIR *d;
+    struct dirent *de;
+    struct ifaddrs *ifa;
+    struct ifaddrs *ifah = NULL;
+
+    if (!ifap)
+        return -1;
+    *ifap = NULL;
+
+    if (ifc_init())
+       return -1;
+
+    d = opendir("/sys/class/net");
+    if (d == 0)
+        return -1;
+    while ((de = readdir(d))) {
+        if (de->d_name[0] == '.')
+            continue;
+        ifa = get_interface(de->d_name, AF_INET);
+        if (ifa != NULL) {
+            ifa->ifa_next = ifah;
+            ifah = ifa;
+        }
+        ifa = get_interface(de->d_name, AF_PACKET);
+        if (ifa != NULL) {
+            ifa->ifa_next = ifah;
+            ifah = ifa;
+        }
+    }
+    *ifap = ifah;
+    closedir(d);
+    ifc_close();
+    return 0;
+}
+
+void freeifaddrs(struct ifaddrs *ifa)
+{
+    struct ifaddrs *ifp;
+
+    while (ifa) {
+        ifp = ifa;
+        free(ifp->ifa_name);
+        if (ifp->ifa_addr)
+            free(ifp->ifa_addr);
+        if (ifp->ifa_netmask)
+            free(ifp->ifa_netmask);
+        ifa = ifa->ifa_next;
+        free(ifp);
+    }
+}
diff --git a/ifaddrs.h b/ifaddrs.h
new file mode 100644
index 0000000..6356653
--- /dev/null
+++ b/ifaddrs.h
@@ -0,0 +1,34 @@
+/****************************************************************************
+ ****************************************************************************
+ ***
+ ***   This header was generated from a glibc header of the same name.
+ ***   It contains only constants, structures, and macros generated from
+ ***   the original header, and thus, contains no copyrightable information.
+ ***
+ ****************************************************************************
+ ****************************************************************************/
+#ifndef _IFADDRS_H
+#define _IFADDRS_H
+
+#include <sys/socket.h>
+
+struct ifaddrs {
+  struct ifaddrs  *ifa_next;
+  char            *ifa_name;
+  unsigned int     ifa_flags;
+  struct sockaddr *ifa_addr;
+  struct sockaddr *ifa_netmask;
+  union {
+    struct sockaddr *ifu_broadaddr;
+    struct sockaddr *ifu_dstaddr;
+  } ifa_ifu;
+#define ifa_broadaddr ifa_ifu.ifu_broadaddr
+#define ifa_dstaddr   ifa_ifu.ifu_dstaddr
+  void            *ifa_data;
+};
+
+extern int getifaddrs(struct ifaddrs **ifap);
+
+extern void freeifaddrs(struct ifaddrs *ifa);
+
+#endif