[PATCH 08/31] resolver: construct comm_addr; honour multiple addresses from the resolver

[Ian Jackson]

We move construction of the comm_addr into the resolver.  The comm_if
and port are supplied to it by site and filled in by the resolver.
This allows the resolver to return a complete comm_addr array.

While we're here, we make an adns_r_addr query instead of an adns_r_a
query.

Signed-off-by: Ian Jackson <ijackson at chiark.greenend.org.uk>
---
 resolver.c |   47 ++++++++++++++++++++++++++++++++++++++++-------
 secnet.h   |   12 ++++++++++--
 site.c     |   24 +++++++-----------------
 3 files changed, 57 insertions(+), 26 deletions(-)

diff --git a/resolver.c b/resolver.c
index 15b8e76..5360966 100644
--- a/resolver.c
+++ b/resolver.c
@@ -2,6 +2,7 @@
 
 #include <errno.h>
 #include "secnet.h"
+#include "util.h"
 #ifndef HAVE_LIBADNS
 #error secnet requires ADNS version 1.0 or above
 #endif
@@ -19,12 +20,15 @@ struct adns {
 
 struct query {
     void *cst;
+    int port;
+    struct comm_if *comm;
     resolve_answer_fn *answer;
     adns_query query;
 };
 
 static resolve_request_fn resolve_request;
 static bool_t resolve_request(void *sst, cstring_t name,
+			      int port, struct comm_if *comm,
 			      resolve_answer_fn *cb, void *cst)
 {
     struct adns *st=sst;
@@ -37,19 +41,25 @@ static bool_t resolve_request(void *sst, cstring_t name,
 	char trimmed[maxlitlen+1];
 	memcpy(trimmed,name+1,l-2);
 	trimmed[l-2]=0;
-	struct in_addr ia;
-	if (inet_aton(trimmed,&ia))
-	    cb(cst,&ia);
+	struct comm_addr ca;
+	FILLZERO(ca);
+	ca.comm=comm;
+	ca.sin.sin_family=AF_INET;
+	ca.sin.sin_port=htons(port);
+	if (inet_aton(trimmed,&ca.sin.sin_addr))
+	    cb(cst,&ca,1);
 	else
-	    cb(cst,0);
+	    cb(cst,0,0);
 	return True;
     }
 
     q=safe_malloc(sizeof *q,"resolve_request");
     q->cst=cst;
+    q->comm=comm;
+    q->port=port;
     q->answer=cb;
 
-    rv=adns_submit(st->ast, name, adns_r_a, 0, q, &q->query);
+    rv=adns_submit(st->ast, name, adns_r_addr, 0, q, &q->query);
     if (rv) {
         Message(M_WARNING,
 		"resolver: failed to submit lookup for %s: %s",name,
@@ -85,11 +95,34 @@ static void resolver_afterpoll(void *sst, struct pollfd *fds, int nfds)
 	if (rv==0) {
 	    q=qp;
 	    if (ans->status!=adns_s_ok) {
-		q->answer(q->cst,NULL); /* Failure */
+		q->answer(q->cst,NULL,0); /* Failure */
 		free(q);
 		free(ans);
 	    } else {
-		q->answer(q->cst,ans->rrs.inaddr);
+		int rslot, wslot;
+		int ca_len=MIN(ans->nrrs,MAX_PEER_ADDRS);
+		struct comm_addr ca_buf[ca_len];
+		FILLZERO(ca_buf);
+		for (rslot=0, wslot=0;
+		     rslot<ans->nrrs && wslot<ca_len;
+		     rslot++) {
+		    adns_rr_addr *ra=&ans->rrs.addr[rslot];
+		    struct comm_addr *ca=&ca_buf[wslot];
+		    ca->comm=q->comm;
+		    /* copy fields individually so we leave holes zeroed: */
+		    switch (ra->addr.sa.sa_family) {
+		    case AF_INET:
+			assert(ra->len == sizeof(ca->sin));
+			ca->sin.sin_family=ra->addr.inet.sin_family;
+			ca->sin.sin_addr=  ra->addr.inet.sin_addr;
+			ca->sin.sin_port=  htons(q->port);
+			wslot++;
+			break;
+		    default:
+			break;
+		    }
+		}
+		q->answer(q->cst,ca_buf,wslot);
 		free(q);
 		free(ans);
 	    }
diff --git a/secnet.h b/secnet.h
index a98d15a..900e699 100644
--- a/secnet.h
+++ b/secnet.h
@@ -13,6 +13,13 @@
 #include <sys/types.h>
 #include <sys/time.h>
 #include <netinet/in.h>
+#include <arpa/inet.h>
+
+#define MAX_PEER_ADDRS 5
+/* send at most this many copies; honour at most that many addresses */
+
+struct comm_if;
+struct comm_addr;
 
 typedef char *string_t;
 typedef const char *cstring_t;
@@ -272,9 +279,10 @@ struct buffer_if;
    type. 'address' will be NULL if there was a problem with the query. It
    will be freed once resolve_answer_fn returns. It is in network byte
    order. */
-/* XXX extend to be able to provide multiple answers */
-typedef void resolve_answer_fn(void *st, struct in_addr *addr);
+typedef void resolve_answer_fn(void *st, const struct comm_addr *addrs,
+			       int naddrs);
 typedef bool_t resolve_request_fn(void *st, cstring_t name,
+				  int remoteport, struct comm_if *comm,
 				  resolve_answer_fn *cb, void *cst);
 struct resolver_if {
     void *st;
diff --git a/site.c b/site.c
index ec3d5f0..b48567a 100644
--- a/site.c
+++ b/site.c
@@ -220,7 +220,7 @@ static struct flagstr log_event_table[]={
 
    */
 
-#define MAX_MOBILE_PEERS_MAX 5 /* send at most this many copies, compiled max */
+#define MAX_MOBILE_PEERS_MAX MAX_PEER_ADDRS /* send at most this many copies */
 
 typedef struct {
     struct timeval last;
@@ -1196,29 +1196,18 @@ static bool_t send_msg(struct site *st)
     }
 }
 
-static void site_resolve_callback(void *sst, struct in_addr *address)
+static void site_resolve_callback(void *sst, const struct comm_addr *addrs,
+				  int naddrs)
 {
     struct site *st=sst;
-    struct comm_addr ca_buf;
-    const struct comm_addr *addrs;
-    int naddrs;
 
     st->resolving=False;
 
-    if (address) {
-	FILLZERO(ca_buf);
-	ca_buf.comm=st->comms[0];
-	ca_buf.sin.sin_family=AF_INET;
-	ca_buf.sin.sin_port=htons(st->remoteport);
-	ca_buf.sin.sin_addr=*address;
-	addrs=&ca_buf;
-	naddrs=1;
-	slog(st,LOG_STATE,"resolution of %s completed: %s",
-	     st->address, comm_addr_to_string(&addrs[0]));;
+    if (naddrs) {
+	slog(st,LOG_STATE,"resolution of %s completed, %d addrs, eg: %s",
+	     st->address, naddrs, comm_addr_to_string(&addrs[0]));;
     } else {
 	slog(st,LOG_ERROR,"resolution of %s failed",st->address);
-	addrs=0;
-	naddrs=0;
     }
 
     switch (st->state) {
@@ -1405,6 +1394,7 @@ static bool_t ensure_resolving(struct site *st)
      * case we have to clear ->resolving again. */
     st->resolving=True;
     bool_t ok = st->resolver->request(st->resolver->st,st->address,
+				      st->remoteport,st->comms[0],
 				      site_resolve_callback,st);
     if (!ok)
 	st->resolving=False;
-- 
1.7.10.4