Refactor dhcp_utils for more flexible uses.

Separate out fetching DHCP results from starting the daemon
(for either discover or renew).

Renamed dhcp_do_request() to dhcp_start().
Renamed dhcp_do_request_renew() to dhcp_start_renew().
Added new dhcp_get_results().

Callers of the prior versions of dhcp_do_request* now separately
call dhcp_get_results().

Bug: 19422416
Change-Id: I05447853d444015e6014661dda1bb177b58fe463

2 files changed, 58 insertions, 69 deletions

diff --git a/include/netutils/dhcp.h b/include/netutils/dhcp.h
index de6bc82..008dbd8 100644
--- a/include/netutils/dhcp.h
+++ b/include/netutils/dhcp.h
@@ -23,26 +23,18 @@
 __BEGIN_DECLS
 
 extern int do_dhcp(char *iname);
-extern int dhcp_do_request(const char *ifname,
-                          char *ipaddr,
-                          char *gateway,
-                          uint32_t *prefixLength,
-                          char *dns[],
-                          char *server,
-                          uint32_t *lease,
-                          char *vendorInfo,
-                          char *domain,
-                          char *mtu);
-extern int dhcp_do_request_renew(const char *ifname,
-                                char *ipaddr,
-                                char *gateway,
-                                uint32_t *prefixLength,
-                                char *dns[],
-                                char *server,
-                                uint32_t *lease,
-                                char *vendorInfo,
-                                char *domain,
-                                char *mtu);
+extern int dhcp_start(const char *ifname);
+extern int dhcp_start_renew(const char *ifname);
+extern int dhcp_get_results(const char *ifname,
+                            char *ipaddr,
+                            char *gateway,
+                            uint32_t *prefixLength,
+                            char *dns[],
+                            char *server,
+                            uint32_t *lease,
+                            char *vendorInfo,
+                            char *domain,
+                            char *mtu);
 extern int dhcp_stop(const char *ifname);
 extern int dhcp_release_lease(const char *ifname);
 extern char *dhcp_get_errmsg();
diff --git a/libnetutils/dhcp_utils.c b/libnetutils/dhcp_utils.c
index e1df874..9b7bd8d 100644
--- a/libnetutils/dhcp_utils.c
+++ b/libnetutils/dhcp_utils.c
@@ -33,7 +33,7 @@ static const char DHCP_CONFIG_PATH[]   = "/system/etc/dhcpcd/dhcpcd.conf";
 static const int NAP_TIME = 200;   /* wait for 200ms at a time */
                                   /* when polling for property values */
 static const char DAEMON_NAME_RENEW[]  = "iprenew";
-static char errmsg[100];
+static char errmsg[100] = "";
 /* interface length for dhcpcd daemon start (dhcpcd_<interface> as defined in init.rc file)
  * or for filling up system properties dhcpcd.<interface>.ipaddress, dhcpcd.<interface>.dns1
  * and other properties on a successful bind
@@ -175,6 +175,47 @@ static const char *ipaddr_to_string(in_addr_t addr)
 }
 
 /*
+ * Get any available DHCP results.
+ */
+int dhcp_get_results(const char *interface,
+                     char *ipaddr,
+                     char *gateway,
+                     uint32_t *prefixLength,
+                     char *dns[],
+                     char *server,
+                     uint32_t *lease,
+                     char *vendorInfo,
+                     char *domain,
+                     char *mtu)
+{
+    char result_prop_name[PROPERTY_KEY_MAX];
+    char prop_value[PROPERTY_VALUE_MAX];
+
+    /* Interface name after converting p2p0-p2p0-X to p2p to reuse system properties */
+    char p2p_interface[MAX_INTERFACE_LENGTH];
+    get_p2p_interface_replacement(interface, p2p_interface);
+    snprintf(result_prop_name, sizeof(result_prop_name), "%s.%s.result",
+            DHCP_PROP_NAME_PREFIX,
+            p2p_interface);
+
+    memset(prop_value, '\0', PROPERTY_VALUE_MAX);
+    if (!property_get(result_prop_name, prop_value, NULL)) {
+        snprintf(errmsg, sizeof(errmsg), "%s", "DHCP result property was not set");
+        return -1;
+    }
+    if (strcmp(prop_value, "ok") == 0) {
+        if (fill_ip_info(interface, ipaddr, gateway, prefixLength, dns,
+                server, lease, vendorInfo, domain, mtu) == -1) {
+            return -1;
+        }
+        return 0;
+    } else {
+        snprintf(errmsg, sizeof(errmsg), "DHCP result was %s", prop_value);
+        return -1;
+    }
+}
+
+/*
  * Start the dhcp client daemon, and wait for it to finish
  * configuring the interface.
  *
@@ -183,16 +224,7 @@ static const char *ipaddr_to_string(in_addr_t addr)
  * Example:
  * service dhcpcd_<interface> /system/bin/dhcpcd -ABKL -f dhcpcd.conf
  */
-int dhcp_do_request(const char *interface,
-                    char *ipaddr,
-                    char *gateway,
-                    uint32_t *prefixLength,
-                    char *dns[],
-                    char *server,
-                    uint32_t *lease,
-                    char *vendorInfo,
-                    char *domain,
-                    char *mtu)
+int dhcp_start(const char *interface)
 {
     char result_prop_name[PROPERTY_KEY_MAX];
     char daemon_prop_name[PROPERTY_KEY_MAX];
@@ -236,22 +268,7 @@ int dhcp_do_request(const char *interface,
         return -1;
     }
 
-    if (!property_get(result_prop_name, prop_value, NULL)) {
-        /* shouldn't ever happen, given the success of wait_for_property() */
-        snprintf(errmsg, sizeof(errmsg), "%s", "DHCP result property was not set");
-        return -1;
-    }
-    if (strcmp(prop_value, "ok") == 0) {
-        char dns_prop_name[PROPERTY_KEY_MAX];
-        if (fill_ip_info(interface, ipaddr, gateway, prefixLength, dns,
-                server, lease, vendorInfo, domain, mtu) == -1) {
-            return -1;
-        }
-        return 0;
-    } else {
-        snprintf(errmsg, sizeof(errmsg), "DHCP result was %s", prop_value);
-        return -1;
-    }
+    return 0;
 }
 
 /**
@@ -327,16 +344,7 @@ char *dhcp_get_errmsg() {
  * service iprenew_<interface> /system/bin/dhcpcd -n
  *
  */
-int dhcp_do_request_renew(const char *interface,
-                    char *ipaddr,
-                    char *gateway,
-                    uint32_t *prefixLength,
-                    char *dns[],
-                    char *server,
-                    uint32_t *lease,
-                    char *vendorInfo,
-                    char *domain,
-                    char *mtu)
+int dhcp_start_renew(const char *interface)
 {
     char result_prop_name[PROPERTY_KEY_MAX];
     char prop_value[PROPERTY_VALUE_MAX] = {'\0'};
@@ -366,16 +374,5 @@ int dhcp_do_request_renew(const char *interface,
         return -1;
     }
 
-    if (!property_get(result_prop_name, prop_value, NULL)) {
-        /* shouldn't ever happen, given the success of wait_for_property() */
-        snprintf(errmsg, sizeof(errmsg), "%s", "DHCP Renew result property was not set");
-        return -1;
-    }
-    if (strcmp(prop_value, "ok") == 0) {
-        return fill_ip_info(interface, ipaddr, gateway, prefixLength, dns,
-                server, lease, vendorInfo, domain, mtu);
-    } else {
-        snprintf(errmsg, sizeof(errmsg), "DHCP Renew result was %s", prop_value);
-        return -1;
-    }
+    return 0;
 }