p2p: Fall back to blocking sockets if the async connection fails

Due to a kernel bug, trying to connect through a non blocking socket
may fail and return POLLHUP. In that case the connection procedure falls
back to using blocking sockets and this needs to be delayed until the
kernel sends a DM to the peer.
This is slightly hackish but this code path should get obsolete once
neard runs on top of 3.10 or later kernels.

diff --git a/plugins/p2p.c b/plugins/p2p.c
index b05395f..26f1e62 100644 (file)
--- a/plugins/p2p.c
+++ b/plugins/p2p.c
@@ -283,6 +283,80 @@ static gboolean p2p_listener_event(GIOChannel *channel, GIOCondition condition,
        return !driver->single_connection;
 }
 
+static int p2p_connect_blocking(uint32_t adapter_idx, uint32_t target_idx,
+                               struct near_ndef_message *ndef,
+                               near_device_io_cb cb,
+                               struct near_p2p_driver *driver)
+{
+       int fd, err = 0;
+       struct timeval timeout;
+       struct sockaddr_nfc_llcp addr;
+
+       DBG("");
+
+       fd = socket(AF_NFC, SOCK_STREAM, NFC_SOCKPROTO_LLCP);
+       if (fd < 0)
+               return -errno;
+
+       memset(&addr, 0, sizeof(struct sockaddr_nfc_llcp));
+       addr.sa_family = AF_NFC;
+       addr.dev_idx = adapter_idx;
+       addr.target_idx = target_idx;
+       addr.nfc_protocol = NFC_PROTO_NFC_DEP;
+       addr.service_name_len = strlen(driver->service_name);
+       strcpy(addr.service_name, driver->service_name);
+
+       timeout.tv_sec = 8;
+       timeout.tv_usec = 0;
+
+       if (setsockopt (fd, SOL_SOCKET, SO_RCVTIMEO, (char *)&timeout,
+                       sizeof(timeout)) < 0)
+               near_error("Could not set the receive timeout\n");
+
+       if (setsockopt (fd, SOL_SOCKET, SO_SNDTIMEO, (char *)&timeout,
+                       sizeof(timeout)) < 0)
+               near_error("Could not set the send timeout\n");
+
+       err = connect(fd, (struct sockaddr *) &addr,
+                       sizeof(struct sockaddr_nfc_llcp));
+       if (err < 0) {
+               near_error("Connect failed  %d", err);
+               close(fd);
+
+               return err;
+       }
+
+       return fd;
+}
+
+static gboolean p2p_push_blocking(gpointer user_data)
+{
+       struct p2p_connect *conn = user_data;
+       int fd, err;
+
+       DBG("");
+
+       fd = p2p_connect_blocking(conn->adapter_idx, conn->target_idx,
+                                 conn->ndef, conn->cb, conn->driver);
+       if (fd < 0) {
+               err = fd;
+               goto out;
+       }
+
+       err = conn->driver->push(fd, conn->adapter_idx, conn->target_idx,
+                                                       conn->ndef, conn->cb);
+
+out:
+       if (err < 0)
+               conn->cb(conn->adapter_idx, conn->target_idx, err);
+
+       g_free(conn->ndef->data);
+       g_free(conn->ndef);
+       g_free(conn);
+
+       return FALSE;
+}
+
 static gboolean check_nval(GIOChannel *io)
 {
        struct pollfd fds;
@@ -316,6 +390,17 @@ static gboolean p2p_connect_event(GIOChannel *channel, GIOCondition condition,
        if ((condition & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) ||
                                                check_nval(channel)) {
                near_error("%s connect error", conn->driver->name);
+
+               if (condition & G_IO_HUP) {
+                       DBG("Trying a blocking connect");
+
+                       close(fd);
+
+                       g_timeout_add(300, p2p_push_blocking, conn);
+
+                       return FALSE;
+               }
+
                err = -EIO;
                goto out;
        }