Added skeletton for having px_info list in each Nsock IOD.

When establishing the tunnel through proxy chain, we need to track status of
each proxy (storing R/W buffers, stats, retries...).

This patch lets proxies store and manage whatever structure they want to have
for this in a Nsock IOD. Since types can differ between proxy types, the
proxy_info are stored as a list of void *, ordered like the proxy nodes.

nsock/src/nsock_proxy.c

@@ -82,9 +82,6 @@ static struct proxy_parser *proxy_parser_new(const char *proxychainstr);
 static void proxy_parser_next(struct proxy_parser *parser);
 static void proxy_parser_delete(struct proxy_parser *parser);
 
-static struct proxy_node *proxy_node_new(char *proxystr);
-static void proxy_node_delete(struct proxy_node *proxy);
-
 
 /* --- Implemented proxy backends --- */
 extern const struct proxy_op proxy_http_ops;
@@ -133,7 +130,7 @@ void nsock_proxychain_delete(nsock_proxychain chain) {
 
     free(pchain->specstr);
     while ((node = (struct proxy_node *)gh_list_pop(&pchain->nodes)) != NULL) {
-      proxy_node_delete(node);
+      node->ops->node_delete(node);
     }
 
     gh_list_free(&pchain->nodes);
@@ -157,17 +154,69 @@ int nsp_set_proxychain(nsock_pool nspool, nsock_proxychain chain) {
 struct proxy_chain_context *proxy_chain_context_new(nsock_pool nspool) {
   mspool *nsp = (mspool *)nspool;
   struct proxy_chain_context *ctx;
+  gh_list_elem *elt;
 
   ctx = (struct proxy_chain_context *)safe_malloc(sizeof(struct proxy_chain_context));
   ctx->px_chain = nsp->px_chain;
   ctx->px_state = PROXY_STATE_INITIAL;
   ctx->px_current = GH_LIST_FIRST_ELEM(&nsp->px_chain->nodes);
+  gh_list_init(&ctx->px_info);
+
+  for (elt = GH_LIST_FIRST_ELEM(&nsp->px_chain->nodes); elt != NULL; elt = GH_LIST_ELEM_NEXT(elt)) {
+    struct proxy_node *px = (struct proxy_node *)GH_LIST_ELEM_DATA(elt);
+    void *pinfo = NULL;
+
+    px->ops->info_new(&pinfo);
+    gh_list_append(&ctx->px_info, pinfo);
+  }
+
   return ctx;
 }
 
 void proxy_chain_context_delete(struct proxy_chain_context *ctx) {
-  if (ctx)
+  if (ctx) {
+    gh_list_elem *pxe;
+
+    assert(GH_LIST_COUNT(&ctx->px_chain->nodes) == GH_LIST_COUNT(&ctx->px_info));
+
+    for (pxe = GH_LIST_FIRST_ELEM(&ctx->px_chain->nodes); pxe != NULL; pxe = GH_LIST_ELEM_NEXT(pxe)) {
+      struct proxy_node *pxn;
+      void *px_info;
+
+      pxn = (struct proxy_node *)GH_LIST_ELEM_DATA(pxe);
+      px_info = gh_list_pop(&ctx->px_info);
+
+      pxn->ops->info_delete(px_info);
+    }
+
+    gh_list_free(&ctx->px_info);
     free(ctx);
+  }
+}
+
+/* XXX
+ * This function is just an ugly PoC.
+ *
+ * A clean version should handle:
+ *   - both v4 and v6 adresses
+ *   - hostnames (how do we want to resolve them though??)
+ *   - user:pass@ prefix before host specification
+ */
+static struct proxy_node *proxy_node_new(char *proxystr) {
+  int i;
+
+  for (i = 0; ProxyBackends[i] != NULL; i++) {
+    const struct proxy_op *pxop;
+
+    pxop = ProxyBackends[i];
+    if (strncasecmp(proxystr, pxop->prefix, strlen(pxop->prefix)) == 0) {
+      struct proxy_node *proxy;
+
+      pxop->node_new(&proxy, proxystr);
+      return proxy;
+    }
+  }
+  fatal("Invalid protocol in proxy specification string: %s", proxystr);
 }
 
 struct proxy_parser *proxy_parser_new(const char *proxychainstr) {
@@ -206,37 +255,6 @@ void proxy_parser_delete(struct proxy_parser *parser) {
   }
 }
 
-/* XXX
- * This function is just an ugly PoC.
- *
- * A clean version should handle:
- *   - both v4 and v6 adresses
- *   - hostnames (how do we want to resolve them though??)
- *   - user:pass@ prefix before host specification
- */
-static struct proxy_node *proxy_node_new(char *proxystr) {
-  int i;
-
-  for (i = 0; ProxyBackends[i] != NULL; i++) {
-    const struct proxy_op *pxop;
-
-    pxop = ProxyBackends[i];
-    if (strncasecmp(proxystr, pxop->prefix, strlen(pxop->prefix)) == 0) {
-      struct proxy_node *proxy;
-
-      proxy = (struct proxy_node *)safe_zalloc(sizeof(struct proxy_node));
-      pxop->init(proxy, proxystr);
-      return proxy;
-    }
-  }
-  fatal("Invalid protocol in proxy specification string: %s", proxystr);
-}
-
-static void proxy_node_delete(struct proxy_node *proxy) {
-  if (proxy)
-    free(proxy);
-}
-
 void forward_event(nsock_pool nspool, nsock_event nsevent, void *udata) {
   mspool *nsp = (mspool *)nspool;
   msevent *nse = (msevent *)nsevent;

nsock/src/nsock_proxy.h

@@ -85,6 +85,9 @@ enum nsock_proxy_state {
 
 /* ------------------- STRUCTURES ------------------- */
 
+/* Static information about a proxy node in the chain. This is generated by
+ * parsing the proxy specification string given by user. Those structures are
+ * then read-only and stored in the nsock_pool. */
 struct proxy_node {
   enum nsock_proxy_type px_type;
 
@@ -95,19 +98,26 @@ struct proxy_node {
   unsigned short port;
 };
 
+/* Ordered list of proxy nodes, as specified in the proxy specification string. */
 struct proxy_chain {
   char *specstr;
   gh_list nodes;
 };
 
+/* IOD-specific context. For each IOD we establish a tunnel through the chain of
+ * proxies. This structure stores all the related information. */
 struct proxy_chain_context {
-  struct proxy_chain *px_chain;
+  const struct proxy_chain *px_chain;
 
   /* Those fields are used to store current state during the tunnel
    * establishment phase. */
   gh_list_elem *px_current;
   enum nsock_proxy_state px_state;
 
+  /* Each proxy in the chain maintains a data structure. This can contains r/w
+   * buffers for instance. */
+  gh_list px_info;
+
   struct sockaddr_storage target_ss;
   size_t target_sslen;
   unsigned short target_port;
@@ -118,10 +128,17 @@ struct proxy_op {
   const char *prefix;
   enum nsock_proxy_type type;
 
-  void (*init)(struct proxy_node *proxy, char *proxystr);
+  int (*node_new)(struct proxy_node **node, char *proxystr);
+  void (*node_delete)(struct proxy_node *node);
+
+  int (*info_new)(void **info);
+  void (*info_delete)(void *info);
+
   void (*handler)(nsock_pool nspool, nsock_event nsevent, void *udata);
+
   nsock_event_id (*connect_tcp)(nsock_pool nsp, nsock_iod ms_iod, nsock_ev_handler handler, int mstimeout,
                                 void *userdata, struct sockaddr *saddr, size_t sslen, unsigned short port);
+
   char *(*encode)(const char *src, size_t len, size_t *dlen);
   char *(*decode)(const char *src, size_t len, size_t *dlen);
 };

nsock/src/proxy_http.c

@@ -61,9 +61,16 @@
 
 #define DEFAULT_PROXY_PORT_HTTP "8080"
 
+struct http_proxy_info {
+  void *dummy;
+};
 
-/* --- PROXY INTERFACE PROTOTYPES --- */
+
-static void proxy_http_init(struct proxy_node *proxy, char *proxystr);
+/* ---- PROTOTYPES ---- */
+static int proxy_http_node_new(struct proxy_node **node, char *proxystr);
+static void proxy_http_node_delete(struct proxy_node *node);
+static int proxy_http_info_new(void **info);
+static void proxy_http_info_delete(void *info);
 static void proxy_http_handler(nsock_pool nspool, nsock_event nsevent, void *udata);
 static nsock_event_id proxy_http_connect_tcp(nsock_pool nsp, nsock_iod ms_iod, nsock_ev_handler handler,
                                              int timeout_msecs, void *userdata, struct sockaddr *saddr,
@@ -76,7 +83,10 @@ static char *proxy_http_decode(const char *src, size_t len, size_t *dlen);
 const struct proxy_op proxy_http_ops = {
   .prefix      = "http://",
   .type        = PROXY_TYPE_HTTP,
-  .init        = proxy_http_init,
+  .node_new    = proxy_http_node_new,
+  .node_delete = proxy_http_node_delete,
+  .info_new    = proxy_http_info_new,
+  .info_delete = proxy_http_info_delete,
   .handler     = proxy_http_handler,
   .connect_tcp = proxy_http_connect_tcp,
   .encode      = proxy_http_encode,
@@ -84,10 +94,12 @@ const struct proxy_op proxy_http_ops = {
 };
 
 
-void proxy_http_init(struct proxy_node *proxy, char *proxystr) {
+int proxy_http_node_new(struct proxy_node **node, char *proxystr) {
   struct sockaddr_in *sin;
+  struct proxy_node *proxy;
   char *strhost, *strport, *saveptr;
 
+  proxy = (struct proxy_node *)safe_zalloc(sizeof(struct proxy_node));
   proxy->ops = &proxy_http_ops;
 
   strhost = strtok_r(proxystr + 7, ":", &saveptr);
@@ -101,6 +113,31 @@ void proxy_http_init(struct proxy_node *proxy, char *proxystr) {
 
   proxy->sslen = sizeof(struct sockaddr_in);
   proxy->port = (unsigned short)atoi(strport);
+
+  *node = proxy;
+
+  return 1;
+}
+
+void proxy_http_node_delete(struct proxy_node *node) {
+  if (node)
+    free(node);
+}
+
+int proxy_http_info_new(void **info) {
+  struct http_proxy_info *pxi;
+
+  pxi = (struct http_proxy_info *)safe_zalloc(sizeof(struct http_proxy_info));
+  pxi->dummy = NULL; // TODO
+
+  *info = pxi;
+
+  return 1;
+}
+
+void proxy_http_info_delete(void *info) {
+  if (info)
+    free(info);
 }
 
 void proxy_http_handler(nsock_pool nspool, nsock_event nsevent, void *udata) {