batman-adv: return netdev status in the TX path

Return the proper netdev TX status along the TX path so that the tp_meter
can understand when the queue is full and should stop sending packets.

Signed-off-by: Antonio Quartulli <antonio.quartulli@open-mesh.com>
Signed-off-by: Sven Eckelmann <sven.eckelmann@open-mesh.com>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

5 files changed, 68 insertions, 44 deletions

diff --git a/net/batman-adv/fragmentation.c b/net/batman-adv/fragmentation.c
index 9f41a0a0d6ab..0934730fb7ff 100644
--- a/net/batman-adv/fragmentation.c
+++ b/net/batman-adv/fragmentation.c
@@ -433,11 +433,12 @@ err:
  * @orig_node: final destination of the created fragments
  * @neigh_node: next-hop of the created fragments
  *
- * Return: true on success, false otherwise.
+ * Return: the netdev tx status or -1 in case of error.
+ * When -1 is returned the skb is not consumed.
  */
-bool batadv_frag_send_packet(struct sk_buff *skb,
-                             struct batadv_orig_node *orig_node,
-                             struct batadv_neigh_node *neigh_node)
+int batadv_frag_send_packet(struct sk_buff *skb,
+                            struct batadv_orig_node *orig_node,
+                            struct batadv_neigh_node *neigh_node)
 {
         struct batadv_priv *bat_priv;
         struct batadv_hard_iface *primary_if = NULL;
@@ -446,7 +447,7 @@ bool batadv_frag_send_packet(struct sk_buff *skb,
         unsigned int mtu = neigh_node->if_incoming->net_dev->mtu;
         unsigned int header_size = sizeof(frag_header);
         unsigned int max_fragment_size, max_packet_size;
-        bool ret = false;
+        int ret = -1;
 
         /* To avoid merge and refragmentation at next-hops we never send
          * fragments larger than BATADV_FRAG_MAX_FRAG_SIZE
@@ -457,12 +458,12 @@ bool batadv_frag_send_packet(struct sk_buff *skb,
 
         /* Don't even try to fragment, if we need more than 16 fragments */
         if (skb->len > max_packet_size)
-                goto out_err;
+                goto out;
 
         bat_priv = orig_node->bat_priv;
         primary_if = batadv_primary_if_get_selected(bat_priv);
         if (!primary_if)
-                goto out_err;
+                goto out;
 
         /* Create one header to be copied to all fragments */
         frag_header.packet_type = BATADV_UNICAST_FRAG;
@@ -488,23 +489,33 @@ bool batadv_frag_send_packet(struct sk_buff *skb,
         while (skb->len > max_fragment_size) {
                 skb_fragment = batadv_frag_create(skb, &frag_header, mtu);
                 if (!skb_fragment)
-                        goto out_err;
+                        goto out;
 
                 batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_TX);
                 batadv_add_counter(bat_priv, BATADV_CNT_FRAG_TX_BYTES,
                                    skb_fragment->len + ETH_HLEN);
-                batadv_send_unicast_skb(skb_fragment, neigh_node);
+                ret = batadv_send_unicast_skb(skb_fragment, neigh_node);
+                if (ret != NET_XMIT_SUCCESS) {
+                        /* return -1 so that the caller can free the original
+                         * skb
+                         */
+                        ret = -1;
+                        goto out;
+                }
+
                 frag_header.no++;
 
                 /* The initial check in this function should cover this case */
-                if (frag_header.no == BATADV_FRAG_MAX_FRAGMENTS - 1)
-                        goto out_err;
+                if (frag_header.no == BATADV_FRAG_MAX_FRAGMENTS - 1) {
+                        ret = -1;
+                        goto out;
+                }
         }
 
         /* Make room for the fragment header. */
         if (batadv_skb_head_push(skb, header_size) < 0 ||
             pskb_expand_head(skb, header_size + ETH_HLEN, 0, GFP_ATOMIC) < 0)
-                goto out_err;
+                goto out;
 
         memcpy(skb->data, &frag_header, header_size);
 
@@ -512,11 +523,9 @@ bool batadv_frag_send_packet(struct sk_buff *skb,
         batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_TX);
         batadv_add_counter(bat_priv, BATADV_CNT_FRAG_TX_BYTES,
                            skb->len + ETH_HLEN);
-        batadv_send_unicast_skb(skb, neigh_node);
+        ret = batadv_send_unicast_skb(skb, neigh_node);
 
-        ret = true;
-
-out_err:
+out:
         if (primary_if)
                 batadv_hardif_put(primary_if);
 
diff --git a/net/batman-adv/fragmentation.h b/net/batman-adv/fragmentation.h
index 9ff77c7ef7c7..3202fe329e63 100644
--- a/net/batman-adv/fragmentation.h
+++ b/net/batman-adv/fragmentation.h
@@ -34,9 +34,9 @@ bool batadv_frag_skb_fwd(struct sk_buff *skb,
                          struct batadv_orig_node *orig_node_src);
 bool batadv_frag_skb_buffer(struct sk_buff **skb,
                             struct batadv_orig_node *orig_node);
-bool batadv_frag_send_packet(struct sk_buff *skb,
-                             struct batadv_orig_node *orig_node,
-                             struct batadv_neigh_node *neigh_node);
+int batadv_frag_send_packet(struct sk_buff *skb,
+                            struct batadv_orig_node *orig_node,
+                            struct batadv_neigh_node *neigh_node);
 
 /**
  * batadv_frag_check_entry - check if a list of fragments has timed out
diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c
index 5833ab3008a1..76de583fe866 100644
--- a/net/batman-adv/routing.c
+++ b/net/batman-adv/routing.c
@@ -270,8 +270,10 @@ static int batadv_recv_my_icmp_packet(struct batadv_priv *bat_priv,
                 icmph->ttl = BATADV_TTL;
 
                 res = batadv_send_skb_to_orig(skb, orig_node, NULL);
-                if (res != NET_XMIT_DROP)
-                        ret = NET_RX_SUCCESS;
+                if (res == -1)
+                        goto out;
+
+                ret = NET_RX_SUCCESS;
 
                 break;
         default:
@@ -292,7 +294,7 @@ static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
         struct batadv_hard_iface *primary_if = NULL;
         struct batadv_orig_node *orig_node = NULL;
         struct batadv_icmp_packet *icmp_packet;
-        int ret = NET_RX_DROP;
+        int res, ret = NET_RX_DROP;
 
         icmp_packet = (struct batadv_icmp_packet *)skb->data;
 
@@ -323,7 +325,8 @@ static int batadv_recv_icmp_ttl_exceeded(struct batadv_priv *bat_priv,
         icmp_packet->msg_type = BATADV_TTL_EXCEEDED;
         icmp_packet->ttl = BATADV_TTL;
 
-        if (batadv_send_skb_to_orig(skb, orig_node, NULL) != NET_XMIT_DROP)
+        res = batadv_send_skb_to_orig(skb, orig_node, NULL);
+        if (res != -1)
                 ret = NET_RX_SUCCESS;
 
 out:
@@ -343,7 +346,7 @@ int batadv_recv_icmp_packet(struct sk_buff *skb,
         struct ethhdr *ethhdr;
         struct batadv_orig_node *orig_node = NULL;
         int hdr_size = sizeof(struct batadv_icmp_header);
-        int ret = NET_RX_DROP;
+        int res, ret = NET_RX_DROP;
 
         /* drop packet if it has not necessary minimum size */
         if (unlikely(!pskb_may_pull(skb, hdr_size)))
@@ -409,7 +412,8 @@ int batadv_recv_icmp_packet(struct sk_buff *skb,
         icmph->ttl--;
 
         /* route it */
-        if (batadv_send_skb_to_orig(skb, orig_node, recv_if) != NET_XMIT_DROP)
+        res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
+        if (res != -1)
                 ret = NET_RX_SUCCESS;
 
 out:
@@ -646,6 +650,8 @@ static int batadv_route_unicast_packet(struct sk_buff *skb,
 
         len = skb->len;
         res = batadv_send_skb_to_orig(skb, orig_node, recv_if);
+        if (res == -1)
+                goto out;
 
         /* translate transmit result into receive result */
         if (res == NET_XMIT_SUCCESS) {
@@ -653,13 +659,10 @@ static int batadv_route_unicast_packet(struct sk_buff *skb,
                 batadv_inc_counter(bat_priv, BATADV_CNT_FORWARD);
                 batadv_add_counter(bat_priv, BATADV_CNT_FORWARD_BYTES,
                                    len + ETH_HLEN);
-
-                ret = NET_RX_SUCCESS;
-        } else if (res == -EINPROGRESS) {
-                /* skb was buffered and consumed */
-                ret = NET_RX_SUCCESS;
         }
 
+        ret = NET_RX_SUCCESS;
+
 out:
         if (orig_node)
                 batadv_orig_node_put(orig_node);
diff --git a/net/batman-adv/send.c b/net/batman-adv/send.c
index 3a59df26ee32..3a10d87b4b76 100644
--- a/net/batman-adv/send.c
+++ b/net/batman-adv/send.c
@@ -20,6 +20,7 @@
 
 #include <linux/atomic.h>
 #include <linux/byteorder/generic.h>
+#include <linux/errno.h>
 #include <linux/etherdevice.h>
 #include <linux/fs.h>
 #include <linux/if.h>
@@ -72,6 +73,7 @@ int batadv_send_skb_packet(struct sk_buff *skb,
 {
         struct batadv_priv *bat_priv;
         struct ethhdr *ethhdr;
+        int ret;
 
         bat_priv = netdev_priv(hard_iface->soft_iface);
 
@@ -109,8 +111,15 @@ int batadv_send_skb_packet(struct sk_buff *skb,
         /* dev_queue_xmit() returns a negative result on error.  However on
          * congestion and traffic shaping, it drops and returns NET_XMIT_DROP
          * (which is > 0). This will not be treated as an error.
+         *
+         * a negative value cannot be returned because it could be interepreted
+         * as not consumed skb by callers of batadv_send_skb_to_orig.
          */
-        return dev_queue_xmit(skb);
+        ret = dev_queue_xmit(skb);
+        if (ret < 0)
+                ret = NET_XMIT_DROP;
+
+        return ret;
 send_skb_err:
         kfree_skb(skb);
         return NET_XMIT_DROP;
@@ -156,8 +165,11 @@ int batadv_send_unicast_skb(struct sk_buff *skb,
  * host, NULL can be passed as recv_if and no interface alternating is
  * attempted.
  *
- * Return: NET_XMIT_SUCCESS on success, NET_XMIT_DROP on failure, or
- * -EINPROGRESS if the skb is buffered for later transmit.
+ * Return: -1 on failure (and the skb is not consumed), -EINPROGRESS if the
+ * skb is buffered for later transmit or the NET_XMIT status returned by the
+ * lower routine if the packet has been passed down.
+ *
+ * If the returning value is not -1 the skb has been consumed.
  */
 int batadv_send_skb_to_orig(struct sk_buff *skb,
                             struct batadv_orig_node *orig_node,
@@ -165,7 +177,7 @@ int batadv_send_skb_to_orig(struct sk_buff *skb,
 {
         struct batadv_priv *bat_priv = orig_node->bat_priv;
         struct batadv_neigh_node *neigh_node;
-        int ret = NET_XMIT_DROP;
+        int ret = -1;
 
         /* batadv_find_router() increases neigh_nodes refcount if found. */
         neigh_node = batadv_find_router(bat_priv, orig_node, recv_if);
@@ -178,8 +190,7 @@ int batadv_send_skb_to_orig(struct sk_buff *skb,
         if (atomic_read(&bat_priv->fragmentation) &&
             skb->len > neigh_node->if_incoming->net_dev->mtu) {
                 /* Fragment and send packet. */
-                if (batadv_frag_send_packet(skb, orig_node, neigh_node))
-                        ret = NET_XMIT_SUCCESS;
+                ret = batadv_frag_send_packet(skb, orig_node, neigh_node);
 
                 goto out;
         }
@@ -188,12 +199,10 @@ int batadv_send_skb_to_orig(struct sk_buff *skb,
          * (i.e. being forwarded). If the packet originates from this node or if
          * network coding fails, then send the packet as usual.
          */
-        if (recv_if && batadv_nc_skb_forward(skb, neigh_node)) {
+        if (recv_if && batadv_nc_skb_forward(skb, neigh_node))
                 ret = -EINPROGRESS;
-        } else {
-                batadv_send_unicast_skb(skb, neigh_node);
-                ret = NET_XMIT_SUCCESS;
-        }
+        else
+                ret = batadv_send_unicast_skb(skb, neigh_node);
 
 out:
         if (neigh_node)
@@ -319,7 +328,7 @@ int batadv_send_skb_unicast(struct batadv_priv *bat_priv,
 {
         struct batadv_unicast_packet *unicast_packet;
         struct ethhdr *ethhdr;
-        int ret = NET_XMIT_DROP;
+        int res, ret = NET_XMIT_DROP;
 
         if (!orig_node)
                 goto out;
@@ -356,7 +365,8 @@ int batadv_send_skb_unicast(struct batadv_priv *bat_priv,
         if (batadv_tt_global_client_is_roaming(bat_priv, ethhdr->h_dest, vid))
                 unicast_packet->ttvn = unicast_packet->ttvn - 1;
 
-        if (batadv_send_skb_to_orig(skb, orig_node, NULL) != NET_XMIT_DROP)
+        res = batadv_send_skb_to_orig(skb, orig_node, NULL);
+        if (res != -1)
                 ret = NET_XMIT_SUCCESS;
 
 out:
diff --git a/net/batman-adv/tvlv.c b/net/batman-adv/tvlv.c
index 2fd542e0d6a8..3d1cf0fb112d 100644
--- a/net/batman-adv/tvlv.c
+++ b/net/batman-adv/tvlv.c
@@ -591,6 +591,7 @@ void batadv_tvlv_unicast_send(struct batadv_priv *bat_priv, u8 *src,
         unsigned char *tvlv_buff;
         unsigned int tvlv_len;
         ssize_t hdr_len = sizeof(*unicast_tvlv_packet);
+        int res;
 
         orig_node = batadv_orig_hash_find(bat_priv, dst);
         if (!orig_node)
@@ -623,7 +624,8 @@ void batadv_tvlv_unicast_send(struct batadv_priv *bat_priv, u8 *src,
         tvlv_buff += sizeof(*tvlv_hdr);
         memcpy(tvlv_buff, tvlv_value, tvlv_value_len);
 
-        if (batadv_send_skb_to_orig(skb, orig_node, NULL) == NET_XMIT_DROP)
+        res = batadv_send_skb_to_orig(skb, orig_node, NULL);
+        if (res == -1)
                 kfree_skb(skb);
 out:
         batadv_orig_node_put(orig_node);