Merge pull request #397 from rpaaron/consistent_resolution_strategy

Consistent resolution strategy

test/probe.py

@@ -268,9 +268,10 @@ class TestProbeICMPv6(mtrpacket.MtrPacketTest):
     '''Test sending probes using IP version 6'''
 
     def __init__(self, *args):
-        google_addr = resolve_ipv6_address(mtrpacket.IPV6_TEST_HOST)
+        if mtrpacket.HAVE_IPV6:
+            google_addr = resolve_ipv6_address(mtrpacket.IPV6_TEST_HOST)
 
-        self.google_addr = google_addr  # type: str
+            self.google_addr = google_addr  # type: str
 
         super(TestProbeICMPv6, self).__init__(*args)
 

ui/dns.c

@@ -87,18 +87,6 @@ static int longipstr(
 }
 
 
-struct hostent *dns_forward(
-    const char *name)
-{
-    struct hostent *host;
-
-    if ((host = gethostbyname(name)))
-        return host;
-    else
-        return NULL;
-}
-
-
 static struct dns_results *findip(
     struct mtr_ctl *ctl,
     ip_t * ip)
@@ -124,7 +112,7 @@ static void set_sockaddr_ip(
 }
 
 void dns_open(
-    sa_family_t family)
+    void)
 {
     int pid;
 
@@ -173,7 +161,8 @@ void dns_open(
 
                 buf[strlen(buf) - 1] = 0;       /* chomp newline. */
 
-                longipstr(buf, &host, family);
+                sa_family_t family = (buf[0] == '4') ? AF_INET : AF_INET6;
+                longipstr(buf +1, &host, family);
                 set_sockaddr_ip(family, &sa, &host);
                 salen = (family == AF_INET) ? sizeof(struct sockaddr_in) :
                     sizeof(struct sockaddr_in6);
@@ -256,7 +245,7 @@ char *dns_lookup2(
     ip_t * ip)
 {
     struct dns_results *r;
-    char buf[INET6_ADDRSTRLEN + 1];
+    char buf[INET6_ADDRSTRLEN + 2]; // af_byte + addr + null
     int rv;
 
     r = findip(ctl, ip);
@@ -270,7 +259,8 @@ char *dns_lookup2(
         r->name = NULL;
         r->next = results;
         results = r;
-        snprintf(buf, sizeof(buf), "%s\n", strlongip(ctl->af, ip));
+        char ip4or6 = (ctl->af == AF_INET) ? '4' : '6';
+        snprintf(buf, sizeof(buf), "%c%s\n", ip4or6, strlongip(ctl->af, ip));
         rv = write(todns[1], buf, strlen(buf));
         if (rv < 0)
             error(0, errno, "couldn't write to resolver process");

ui/dns.h

@@ -23,7 +23,7 @@
 /*  Prototypes for dns.c  */
 
 extern void dns_open(
-    sa_family_t family);
+    void);
 extern int dns_waitfd(
     void);
 extern void dns_ack(
@@ -41,8 +41,6 @@ extern char *dns_lookup(
 extern char *dns_lookup2(
     struct mtr_ctl *ctl,
     ip_t * address);
-extern struct hostent *dns_forward(
-    const char *name);
 extern char *strlongip(
     sa_family_t family,
     ip_t * ip);

ui/gtk.c

@@ -244,11 +244,13 @@ static gint Host_activate(
     gpointer data)
 {
     struct mtr_ctl *ctl = (struct mtr_ctl *) data;
-    struct hostent *addr;
+    struct addrinfo *res = NULL;
 
-    addr = dns_forward(gtk_entry_get_text(GTK_ENTRY(entry)));
-    if (addr) {
-        net_reopen(ctl, addr);
+    ctl->af = DEFAULT_AF;  // should this obey the cmd line option?
+    ctl->Hostname = gtk_entry_get_text(GTK_ENTRY(entry));
+    if (get_addrinfo_from_name(ctl, &res, ctl->Hostname) == 0) {
+        net_reopen(ctl, res);
+        freeaddrinfo(res);
         net_send_batch(ctl);
         /* If we are "Paused" at this point it is usually because someone
            entered a non-existing host. Therefore do the go-ahead... */

ui/mtr.c

@@ -38,7 +38,6 @@
 #include <sys/limits.h>
 #endif
 
-#include <netdb.h>
 #include <netinet/in.h>
 #include <sys/socket.h>
 #include <ctype.h>
@@ -63,13 +62,6 @@
 #include "portability/getopt.h"
 #endif
 
-#ifdef ENABLE_IPV6
-#define DEFAULT_AF AF_UNSPEC
-#else
-#define DEFAULT_AF AF_INET
-#endif
-
-
 char *myname;
 
 const struct fields data_fields[MAXFLD] = {
@@ -696,31 +688,25 @@ static void init_rand(
     srand((getpid() << 16) ^ getuid() ^ tv.tv_sec ^ tv.tv_usec);
 }
 
-
 /*
     For historical reasons, we need a hostent structure to represent
     our remote target for probing.  The obsolete way of doing this
     would be to use gethostbyname().  We'll use getaddrinfo() instead
     to generate the hostent.
 */
-static int get_hostent_from_name(
+int get_addrinfo_from_name(
     struct mtr_ctl *ctl,
-    struct hostent *host,
-    const char *name,
-    char **alptr)
+    struct addrinfo **res,
+    const char *name)
 {
     int gai_error;
-    struct addrinfo hints, *res;
-    struct sockaddr_in *sa4;
-#ifdef ENABLE_IPV6
-    struct sockaddr_in6 *sa6;
-#endif
+    struct addrinfo hints;
 
     /* gethostbyname2() is deprecated so we'll use getaddrinfo() instead. */
     memset(&hints, 0, sizeof hints);
     hints.ai_family = ctl->af;
     hints.ai_socktype = SOCK_DGRAM;
-    gai_error = getaddrinfo(name, NULL, &hints, &res);
+    gai_error = getaddrinfo(name, NULL, &hints, res);
     if (gai_error) {
         if (gai_error == EAI_SYSTEM)
             error(0, 0, "Failed to resolve host: %s", name);
@@ -731,33 +717,7 @@ static int get_hostent_from_name(
         return -1;
     }
 
-    /* Convert the first addrinfo into a hostent. */
-    memset(host, 0, sizeof(struct hostent));
-    host->h_name = res->ai_canonname;
-    host->h_aliases = NULL;
-    host->h_addrtype = res->ai_family;
-    ctl->af = res->ai_family;
-    host->h_length = res->ai_addrlen;
-    host->h_addr_list = alptr;
-    switch (ctl->af) {
-    case AF_INET:
-        sa4 = (struct sockaddr_in *) res->ai_addr;
-        alptr[0] = (void *) &(sa4->sin_addr);
-        break;
-#ifdef ENABLE_IPV6
-    case AF_INET6:
-        sa6 = (struct sockaddr_in6 *) res->ai_addr;
-        alptr[0] = (void *) &(sa6->sin6_addr);
-        break;
-#endif
-    default:
-        error(0, 0, "unknown address type");
-
-        errno = EINVAL;
-        return -1;
-    }
-    alptr[1] = NULL;
-
+    ctl->af = (*res)->ai_family;
     return 0;
 }
 
@@ -766,9 +726,6 @@ int main(
     int argc,
     char **argv)
 {
-    struct hostent *host = NULL;
-    struct hostent trhost;
-    char *alptr[2];
     names_t *names_head = NULL;
     names_t *names_walk;
 
@@ -837,8 +794,8 @@ int main(
                      sizeof(ctl.LocalHostname));
         }
 
-        host = &trhost;
-        if (get_hostent_from_name(&ctl, host, ctl.Hostname, alptr) != 0) {
+        struct addrinfo *res = NULL;
+        if (get_addrinfo_from_name(&ctl, &res, ctl.Hostname) != 0) {
             if (ctl.Interactive)
                 exit(EXIT_FAILURE);
             else {
@@ -847,7 +804,7 @@ int main(
             }
         }
 
-        if (net_open(&ctl, host) != 0) {
+        if (net_open(&ctl, res) != 0) {
             error(0, 0, "Unable to start net module");
             if (ctl.Interactive)
                 exit(EXIT_FAILURE);
@@ -857,8 +814,10 @@ int main(
             }
         }
 
+        freeaddrinfo(res);
+
         lock(stdout);
-        dns_open(ctl.af);
+        dns_open();
         display_open(&ctl);
 
         display_loop(&ctl);

ui/mtr.h

@@ -23,6 +23,7 @@
 #include "config.h"
 
 #include <stdint.h>
+#include <netdb.h>
 #include <sys/socket.h>
 #include <arpa/inet.h>
 
@@ -32,8 +33,10 @@
 
 /* Typedefs */
 #ifdef ENABLE_IPV6
+#define DEFAULT_AF AF_UNSPEC
 typedef struct in6_addr ip_t;
 #else
+#define DEFAULT_AF AF_INET
 typedef struct in_addr ip_t;
 #endif
 
@@ -82,7 +85,7 @@ struct mtr_ctl {
     int MaxPing;
     float WaitTime;
     float GraceTime;
-    char *Hostname;
+    const char *Hostname;
     char *InterfaceName;
     char *InterfaceAddress;
     char LocalHostname[128];
@@ -146,4 +149,9 @@ struct mplslen {
 #define running_as_root() (getuid() == 0)
 #endif
 
+int get_addrinfo_from_name(
+    struct mtr_ctl *ctl,
+    struct addrinfo **res,
+    const char *name);
+
 #endif                          /* MTR_MTR_H */

ui/net.c

@@ -736,7 +736,7 @@ static void net_find_local_address(
 
 int net_open(
     struct mtr_ctl *ctl,
-    struct hostent *hostent)
+    struct addrinfo *res)
 {
     int err;
 
@@ -746,7 +746,7 @@ int net_open(
         return err;
     }
 
-    net_reopen(ctl, hostent);
+    net_reopen(ctl, res);
 
     return 0;
 }
@@ -754,7 +754,7 @@ int net_open(
 
 void net_reopen(
     struct mtr_ctl *ctl,
-    struct hostent *hostent)
+    struct addrinfo *res)
 {
     int at;
 
@@ -764,9 +764,9 @@ void net_reopen(
 
     net_reset(ctl);
 
-    ctl->af = remotesockaddr->sa_family = sourcesockaddr->sa_family = hostent->h_addrtype;
+    ctl->af = remotesockaddr->sa_family = sourcesockaddr->sa_family = res->ai_family;
     remoteaddress = sockaddr_addr_offset(remotesockaddr);
-    memcpy(remoteaddress, hostent->h_addr, sockaddr_addr_size(remotesockaddr));
+    memcpy(remoteaddress, sockaddr_addr_offset(res->ai_addr), sockaddr_addr_size(remotesockaddr));
     inet_ntop(remotesockaddr->sa_family, remoteaddress, remoteaddr, sizeof(remoteaddr));
 
     sourceaddress = sockaddr_addr_offset(sourcesockaddr);

ui/net.h

@@ -33,10 +33,10 @@
 
 extern int net_open(
     struct mtr_ctl *ctl,
-    struct hostent *host);
+    struct addrinfo *res);
 extern void net_reopen(
     struct mtr_ctl *ctl,
-    struct hostent *address);
+    struct addrinfo *res);
 extern void net_reset(
     struct mtr_ctl *ctl);
 extern void net_close(