ipcpd: Add DHT as directory in normal IPCP

This implements a Distributed Hash Table (DHT) based on the Kademlia
protocol, with default parameters set as used in the BitTorrent
Mainline DHT. This initial implementation is almost feature complete,
except for some things to be done after a testing period: caching and
stale peer bumping, and setting the expiration timeout via the IRM
tool.

1 files changed, 14 insertions, 47 deletions

diff --git a/src/ipcpd/normal/fa.c b/src/ipcpd/normal/fa.c
index 26ee9037..6e880067 100644
--- a/src/ipcpd/normal/fa.c
+++ b/src/ipcpd/normal/fa.c
@@ -30,6 +30,7 @@
 #include <ouroboros/dev.h>
 #include <ouroboros/ipcp-dev.h>
 
+#include "dir.h"
 #include "dt_pci.h"
 #include "fa.h"
 #include "sdu_sched.h"
@@ -79,8 +80,8 @@ static void destroy_conn(int fd)
         fa.r_addr[fd] = INVALID_ADDR;
 }
 
-static int fa_post_sdu(void *               ae,
-                       struct shm_du_buff * sdb)
+static void fa_post_sdu(void *               ae,
+                        struct shm_du_buff * sdb)
 {
         struct timespec    ts  = {0, TIMEOUT * 1000};
         int                fd;
@@ -99,7 +100,8 @@ static int fa_post_sdu(void *               ae,
                                      shm_du_buff_head(sdb));
         if (msg == NULL) {
                 log_err("Failed to unpack flow alloc message.");
-                return -1;
+                ipcp_sdb_release(sdb);
+                return;
         }
 
         switch (msg->code) {
@@ -110,7 +112,8 @@ static int fa_post_sdu(void *               ae,
                         log_err("Bad flow request.");
                         pthread_mutex_unlock(&ipcpi.alloc_lock);
                         flow_alloc_msg__free_unpacked(msg, NULL);
-                        return -1;
+                        ipcp_sdb_release(sdb);
+                        return;
                 }
 
                 while (ipcpi.alloc_id != -1 &&
@@ -123,7 +126,8 @@ static int fa_post_sdu(void *               ae,
                         log_dbg("Won't allocate over non-operational IPCP.");
                         pthread_mutex_unlock(&ipcpi.alloc_lock);
                         flow_alloc_msg__free_unpacked(msg, NULL);
-                        return -1;
+                        ipcp_sdb_release(sdb);
+                        return;
                 }
 
                 assert(ipcpi.alloc_id == -1);
@@ -136,7 +140,8 @@ static int fa_post_sdu(void *               ae,
                         pthread_mutex_unlock(&ipcpi.alloc_lock);
                         flow_alloc_msg__free_unpacked(msg, NULL);
                         log_err("Failed to get fd for flow.");
-                        return -1;
+                        ipcp_sdb_release(sdb);
+                        return;
                 }
 
                 pthread_rwlock_wrlock(&fa.flows_lock);
@@ -168,13 +173,12 @@ static int fa_post_sdu(void *               ae,
         default:
                 log_err("Got an unknown flow allocation message.");
                 flow_alloc_msg__free_unpacked(msg, NULL);
-                return -1;
+                ipcp_sdb_release(sdb);
+                return;
         }
 
         flow_alloc_msg__free_unpacked(msg, NULL);
         ipcp_sdb_release(sdb);
-
-        return 0;
 }
 
 int fa_init(void)
@@ -235,47 +239,10 @@ int fa_alloc(int             fd,
              qoscube_t       qc)
 {
         flow_alloc_msg_t     msg = FLOW_ALLOC_MSG__INIT;
-        char                 path[RIB_MAX_PATH_LEN + 1];
         uint64_t             addr;
-        ssize_t              ch;
-        ssize_t              i;
-        char **              children;
-        char                 hashstr[ipcp_dir_hash_strlen() + 1];
-        char *               dst_ipcp = NULL;
         struct shm_du_buff * sdb;
 
-        ipcp_hash_str(hashstr, dst);
-
-        assert(strlen(hashstr) + strlen(DIR_PATH) + 1
-               < RIB_MAX_PATH_LEN);
-
-        strcpy(path, DIR_PATH);
-
-        rib_path_append(path, hashstr);
-
-        ch = rib_children(path, &children);
-        if (ch <= 0)
-                return -1;
-
-        for (i = 0; i < ch; ++i)
-                if (dst_ipcp == NULL && strcmp(children[i], ipcpi.name) != 0)
-                        dst_ipcp = children[i];
-                else
-                        free(children[i]);
-
-        free(children);
-
-        if (dst_ipcp == NULL)
-                return -1;
-
-        strcpy(path, MEMBERS_PATH);
-
-        rib_path_append(path, dst_ipcp);
-
-        free(dst_ipcp);
-
-        if (rib_read(path, &addr, sizeof(addr)) != sizeof(addr))
-                return -1;
+        addr = dir_query(dst);
 
         msg.code         = FLOW_ALLOC_CODE__FLOW_REQ;
         msg.has_hash     = true;