Author: marek Date: 2010-07-11 16:34:12 +0200 (Sun, 11 Jul 2010) New Revision: 1737
Modified: trunk/batman-adv/Makefile.kbuild trunk/batman-adv/bat_sysfs.c trunk/batman-adv/hard-interface.c trunk/batman-adv/originator.c trunk/batman-adv/packet.h trunk/batman-adv/routing.c trunk/batman-adv/routing.h trunk/batman-adv/soft-interface.c trunk/batman-adv/types.h Log: batman-adv: layer2 unicast packet fragmentation
This patch implements a simple layer2 fragmentation to allow traffic exchange over network interfaces with a MTU smaller than 1500 bytes. The fragmentation splits the big packets into two parts and marks the frames accordingly. The receiving end buffers the packets to reassemble the orignal packet before passing it to the higher layers. This feature makes it necessary to modify the batman-adv encapsulation for unicast packets by adding a sequence number, flags and the originator address. This modifcation is part of a seperate packet type for fragemented packets to keep the original overhead as low as possible. This patch enables the feature by default to ensure the data traffic can travel through the network. But it also prints a warning to notify the user about the performance implications.
Note: Fragmentation should be avoided at all costs since it has a dramatic impact on the performance, especially when it comes wifi networks. Instead of a single packet, 2 packets have to be sent! Not only valuable airtime is wasted but also packetloss decreases the throughput. A link with 50% packetloss and fragmentation enabled is pretty much unusable.
Signed-off-by: Andreas Langer <an.langer at gmx.de>
Modified: trunk/batman-adv/Makefile.kbuild =================================================================== --- trunk/batman-adv/Makefile.kbuild 2010-07-11 14:34:10 UTC (rev 1736) +++ trunk/batman-adv/Makefile.kbuild 2010-07-11 14:34:12 UTC (rev 1737) @@ -32,4 +32,4 @@ endif
obj-m += batman-adv.o -batman-adv-objs := main.o bat_debugfs.o bat_sysfs.o send.o routing.o soft-interface.o icmp_socket.o translation-table.o bitarray.o hash.o ring_buffer.o vis.o hard-interface.o aggregation.o originator.o gateway_common.o gateway_client.o $(shell [ "2" -eq "$(VERSION)" ] 2>&- && [ "6" -eq "$(PATCHLEVEL)" ] 2>&- && [ "$(SUBLEVEL)" -le "28" ] 2>&- && echo bat_printk.o) +batman-adv-objs := main.o bat_debugfs.o bat_sysfs.o send.o routing.o soft-interface.o icmp_socket.o translation-table.o bitarray.o hash.o ring_buffer.o vis.o hard-interface.o aggregation.o originator.o gateway_common.o gateway_client.o fragmentation.o $(shell [ "2" -eq "$(VERSION)" ] 2>&- && [ "6" -eq "$(PATCHLEVEL)" ] 2>&- && [ "$(SUBLEVEL)" -le "28" ] 2>&- && echo bat_printk.o)
Modified: trunk/batman-adv/bat_sysfs.c =================================================================== --- trunk/batman-adv/bat_sysfs.c 2010-07-11 14:34:10 UTC (rev 1736) +++ trunk/batman-adv/bat_sysfs.c 2010-07-11 14:34:12 UTC (rev 1737) @@ -137,6 +137,58 @@ return count; }
+static ssize_t show_frag(struct kobject *kobj, struct attribute *attr, + char *buff) +{ + struct device *dev = to_dev(kobj->parent); + struct bat_priv *bat_priv = netdev_priv(to_net_dev(dev)); + int frag_status = atomic_read(&bat_priv->frag_enabled); + + return sprintf(buff, "%s\n", + frag_status == 0 ? "disabled" : "enabled"); +} + +static ssize_t store_frag(struct kobject *kobj, struct attribute *attr, + char *buff, size_t count) +{ + struct device *dev = to_dev(kobj->parent); + struct net_device *net_dev = to_net_dev(dev); + struct bat_priv *bat_priv = netdev_priv(net_dev); + int frag_enabled_tmp = -1; + + if (((count == 2) && (buff[0] == '1')) || + (strncmp(buff, "enable", 6) == 0)) + frag_enabled_tmp = 1; + + if (((count == 2) && (buff[0] == '0')) || + (strncmp(buff, "disable", 7) == 0)) + frag_enabled_tmp = 0; + + if (frag_enabled_tmp < 0) { + if (buff[count - 1] == '\n') + buff[count - 1] = '\0'; + + bat_err(net_dev, + "Invalid parameter for 'fragmentation' setting on mesh" + "received: %s\n", buff); + return -EINVAL; + } + + if (atomic_read(&bat_priv->frag_enabled) == frag_enabled_tmp) + return count; + + bat_info(net_dev, "Changing fragmentation from: %s to: %s\n", + atomic_read(&bat_priv->frag_enabled) == 1 ? + "enabled" : "disabled", + frag_enabled_tmp == 1 ? "enabled" : "disabled"); + + atomic_set(&bat_priv->frag_enabled, (unsigned)frag_enabled_tmp); + + update_min_mtu(); + + return count; +} + static ssize_t show_vis_mode(struct kobject *kobj, struct attribute *attr, char *buff) { @@ -325,6 +377,7 @@ static BAT_ATTR(aggregated_ogms, S_IRUGO | S_IWUSR, show_aggr_ogms, store_aggr_ogms); static BAT_ATTR(bonding, S_IRUGO | S_IWUSR, show_bond, store_bond); +static BAT_ATTR(fragmentation, S_IRUGO | S_IWUSR, show_frag, store_frag); static BAT_ATTR(vis_mode, S_IRUGO | S_IWUSR, show_vis_mode, store_vis_mode); static BAT_ATTR(gw_mode, S_IRUGO | S_IWUSR, show_gw_mode, store_gw_mode); static BAT_ATTR(orig_interval, S_IRUGO | S_IWUSR, @@ -336,6 +389,7 @@ static struct bat_attribute *mesh_attrs[] = { &bat_attr_aggregated_ogms, &bat_attr_bonding, + &bat_attr_fragmentation, &bat_attr_vis_mode, &bat_attr_gw_mode, &bat_attr_orig_interval, @@ -356,6 +410,7 @@ routine as soon as we have it */ atomic_set(&bat_priv->aggregation_enabled, 1); atomic_set(&bat_priv->bonding_enabled, 0); + atomic_set(&bat_priv->frag_enabled, 1); atomic_set(&bat_priv->vis_mode, VIS_TYPE_CLIENT_UPDATE); atomic_set(&bat_priv->gw_mode, GW_MODE_OFF); atomic_set(&bat_priv->gw_class, 0);
Modified: trunk/batman-adv/hard-interface.c =================================================================== --- trunk/batman-adv/hard-interface.c 2010-07-11 14:34:10 UTC (rev 1736) +++ trunk/batman-adv/hard-interface.c 2010-07-11 14:34:12 UTC (rev 1737) @@ -166,7 +166,12 @@ /* allow big frames if all devices are capable to do so * (have MTU > 1500 + BAT_HEADER_LEN) */ int min_mtu = ETH_DATA_LEN; + /* FIXME: each batman_if will be attached to a softif */ + struct bat_priv *bat_priv = netdev_priv(soft_device);
+ if (atomic_read(&bat_priv->frag_enabled)) + goto out; + rcu_read_lock(); list_for_each_entry_rcu(batman_if, &if_list, list) { if ((batman_if->if_status == IF_ACTIVE) || @@ -175,7 +180,7 @@ min_mtu); } rcu_read_unlock(); - +out: return min_mtu; }
@@ -265,8 +270,30 @@ orig_hash_add_if(batman_if, bat_priv->num_ifaces);
atomic_set(&batman_if->seqno, 1); + atomic_set(&batman_if->frag_seqno, 1); bat_info(soft_device, "Adding interface: %s\n", batman_if->dev);
+ if (atomic_read(&bat_priv->frag_enabled) && batman_if->net_dev->mtu < + ETH_DATA_LEN + BAT_HEADER_LEN) + bat_info(soft_device, + "The MTU of interface %s is too small (%i) to handle " + "the transport of batman-adv packets. Packets going " + "over this interface will be fragmented on layer2 " + "which could impact the performance. Setting the MTU " + "to %zi would solve the problem.\n", + batman_if->dev, batman_if->net_dev->mtu, + ETH_DATA_LEN + BAT_HEADER_LEN); + + if (!atomic_read(&bat_priv->frag_enabled) && batman_if->net_dev->mtu < + ETH_DATA_LEN + BAT_HEADER_LEN) + bat_info(soft_device, + "The MTU of interface %s is too small (%i) to handle " + "the transport of batman-adv packets. If you experience" + " problems getting traffic through try increasing the " + "MTU to %zi.\n", + batman_if->dev, batman_if->net_dev->mtu, + ETH_DATA_LEN + BAT_HEADER_LEN); + if (hardif_is_iface_up(batman_if)) hardif_activate_interface(soft_device, bat_priv, batman_if); else @@ -515,6 +542,11 @@ ret = recv_unicast_packet(skb, batman_if); break;
+ /* fragmented unicast packet */ + case BAT_UNICAST_FRAG: + ret = recv_ucast_frag_packet(skb, batman_if); + break; + /* broadcast packet */ case BAT_BCAST: ret = recv_bcast_packet(skb);
Modified: trunk/batman-adv/originator.c =================================================================== --- trunk/batman-adv/originator.c 2010-07-11 14:34:10 UTC (rev 1736) +++ trunk/batman-adv/originator.c 2010-07-11 14:34:12 UTC (rev 1737) @@ -29,6 +29,7 @@ #include "compat.h" #include "gateway_client.h" #include "hard-interface.h" +#include "fragmentation.h"
static DECLARE_DELAYED_WORK(purge_orig_wq, purge_orig);
@@ -97,6 +98,7 @@ kfree(neigh_node); }
+ frag_list_free(&orig_node->frag_list); hna_global_del_orig(orig_node, "originator timed out");
kfree(orig_node->bcast_own); @@ -159,6 +161,10 @@
size = bat_priv->num_ifaces * sizeof(uint8_t); orig_node->bcast_own_sum = kzalloc(size, GFP_ATOMIC); + + INIT_LIST_HEAD(&orig_node->frag_list); + orig_node->last_frag_packet = 0; + if (!orig_node->bcast_own_sum) goto free_bcast_own;
@@ -275,6 +281,10 @@ hash_remove_bucket(orig_hash, &hashit); free_orig_node(orig_node); } + + if (time_after(jiffies, (orig_node->last_frag_packet + + msecs_to_jiffies(FRAG_TIMEOUT)))) + frag_list_free(&orig_node->frag_list); }
spin_unlock_irqrestore(&orig_hash_lock, flags);
Modified: trunk/batman-adv/packet.h =================================================================== --- trunk/batman-adv/packet.h 2010-07-11 14:34:10 UTC (rev 1736) +++ trunk/batman-adv/packet.h 2010-07-11 14:34:12 UTC (rev 1737) @@ -24,14 +24,15 @@
#define ETH_P_BATMAN 0x4305 /* unofficial/not registered Ethertype */
-#define BAT_PACKET 0x01 -#define BAT_ICMP 0x02 -#define BAT_UNICAST 0x03 -#define BAT_BCAST 0x04 -#define BAT_VIS 0x05 +#define BAT_PACKET 0x01 +#define BAT_ICMP 0x02 +#define BAT_UNICAST 0x03 +#define BAT_BCAST 0x04 +#define BAT_VIS 0x05 +#define BAT_UNICAST_FRAG 0x06
/* this file is included by batctl which needs these defines */ -#define COMPAT_VERSION 10 +#define COMPAT_VERSION 12 #define DIRECTLINK 0x40 #define VIS_SERVER 0x20 #define PRIMARIES_FIRST_HOP 0x10 @@ -47,6 +48,9 @@ #define VIS_TYPE_SERVER_SYNC 0 #define VIS_TYPE_CLIENT_UPDATE 1
+/* fragmentation defines */ +#define UNI_FRAG_HEAD 0x01 + struct batman_packet { uint8_t packet_type; uint8_t version; /* batman version field */ @@ -98,6 +102,16 @@ uint8_t ttl; } __attribute__((packed));
+struct unicast_frag_packet { + uint8_t packet_type; + uint8_t version; /* batman version field */ + uint8_t dest[6]; + uint8_t ttl; + uint8_t flags; + uint8_t orig[6]; + uint16_t seqno; +} __attribute__((packed)); + struct bcast_packet { uint8_t packet_type; uint8_t version; /* batman version field */
Modified: trunk/batman-adv/routing.c =================================================================== --- trunk/batman-adv/routing.c 2010-07-11 14:34:10 UTC (rev 1736) +++ trunk/batman-adv/routing.c 2010-07-11 14:34:12 UTC (rev 1737) @@ -34,6 +34,7 @@ #include "aggregation.h" #include "compat.h" #include "gateway_client.h" +#include "fragmentation.h"
static DECLARE_WAIT_QUEUE_HEAD(thread_wait);
@@ -1105,43 +1106,43 @@ return router; }
-int recv_unicast_packet(struct sk_buff *skb, struct batman_if *recv_if) +static int check_unicast_packet(struct sk_buff *skb, int hdr_size) { - struct unicast_packet *unicast_packet; - struct orig_node *orig_node; - struct neigh_node *router; struct ethhdr *ethhdr; - struct batman_if *batman_if; - struct sk_buff *skb_old; - uint8_t dstaddr[ETH_ALEN]; - int hdr_size = sizeof(struct unicast_packet); - unsigned long flags;
/* drop packet if it has not necessary minimum size */ if (skb_headlen(skb) < hdr_size) - return NET_RX_DROP; + return -1;
ethhdr = (struct ethhdr *) skb_mac_header(skb);
/* packet with unicast indication but broadcast recipient */ if (is_bcast(ethhdr->h_dest)) - return NET_RX_DROP; + return -1;
/* packet with broadcast sender address */ if (is_bcast(ethhdr->h_source)) - return NET_RX_DROP; + return -1;
/* not for me */ if (!is_my_mac(ethhdr->h_dest)) - return NET_RX_DROP; + return -1;
- unicast_packet = (struct unicast_packet *) skb->data; + return 0; +}
- /* packet for me */ - if (is_my_mac(unicast_packet->dest)) { - interface_rx(skb, hdr_size); - return NET_RX_SUCCESS; - } +static int route_unicast_packet(struct sk_buff *skb, struct batman_if *recv_if, + int hdr_size) +{ + struct orig_node *orig_node; + struct neigh_node *router; + struct batman_if *batman_if; + struct sk_buff *skb_old; + uint8_t dstaddr[ETH_ALEN]; + unsigned long flags; + struct unicast_packet *unicast_packet = + (struct unicast_packet *) skb->data; + struct ethhdr *ethhdr = (struct ethhdr *) skb_mac_header(skb);
/* TTL exceeded */ if (unicast_packet->ttl < 2) { @@ -1172,7 +1173,7 @@ spin_unlock_irqrestore(&orig_hash_lock, flags);
/* create a copy of the skb, if needed, to modify it. */ - if (!skb_clone_writable(skb, sizeof(struct unicast_packet))) { + if (!skb_clone_writable(skb, hdr_size)) { skb_old = skb; skb = skb_copy(skb, GFP_ATOMIC); if (!skb) @@ -1191,6 +1192,80 @@ return NET_RX_SUCCESS; }
+int recv_unicast_packet(struct sk_buff *skb, struct batman_if *recv_if) +{ + struct unicast_packet *unicast_packet; + int hdr_size = sizeof(struct unicast_packet); + + if (check_unicast_packet(skb, hdr_size) < 0) + return NET_RX_DROP; + + unicast_packet = (struct unicast_packet *) skb->data; + + /* packet for me */ + if (is_my_mac(unicast_packet->dest)) { + interface_rx(skb, hdr_size); + return NET_RX_SUCCESS; + } + + return route_unicast_packet(skb, recv_if, hdr_size); +} + +int recv_ucast_frag_packet(struct sk_buff *skb, struct batman_if *recv_if) +{ + struct unicast_frag_packet *unicast_packet; + struct orig_node *orig_node; + struct frag_packet_list_entry *tmp_frag_entry; + int hdr_size = sizeof(struct unicast_frag_packet); + unsigned long flags; + + if (check_unicast_packet(skb, hdr_size) < 0) + return NET_RX_DROP; + + unicast_packet = (struct unicast_frag_packet *) skb->data; + + /* packet for me */ + if (is_my_mac(unicast_packet->dest)) { + + spin_lock_irqsave(&orig_hash_lock, flags); + orig_node = ((struct orig_node *) + hash_find(orig_hash, unicast_packet->orig)); + + if (!orig_node) { + pr_warning("couldn't find orig node for " + "fragmentation\n"); + spin_unlock_irqrestore(&orig_hash_lock, flags); + return NET_RX_DROP; + } + + orig_node->last_frag_packet = jiffies; + + if (list_empty(&orig_node->frag_list)) + create_frag_buffer(&orig_node->frag_list); + + tmp_frag_entry = + search_frag_packet(&orig_node->frag_list, + unicast_packet); + + if (!tmp_frag_entry) { + create_frag_entry(&orig_node->frag_list, skb); + spin_unlock_irqrestore(&orig_hash_lock, flags); + return NET_RX_SUCCESS; + } + + skb = merge_frag_packet(&orig_node->frag_list, + tmp_frag_entry, skb); + spin_unlock_irqrestore(&orig_hash_lock, flags); + if (!skb) + return NET_RX_DROP; + + interface_rx(skb, hdr_size); + return NET_RX_SUCCESS; + } + + return route_unicast_packet(skb, recv_if, hdr_size); +} + int recv_bcast_packet(struct sk_buff *skb) { struct orig_node *orig_node;
Modified: trunk/batman-adv/routing.h =================================================================== --- trunk/batman-adv/routing.h 2010-07-11 14:34:10 UTC (rev 1736) +++ trunk/batman-adv/routing.h 2010-07-11 14:34:12 UTC (rev 1737) @@ -34,6 +34,7 @@ unsigned char *hna_buff, int hna_buff_len); int recv_icmp_packet(struct sk_buff *skb); int recv_unicast_packet(struct sk_buff *skb, struct batman_if *recv_if); +int recv_ucast_frag_packet(struct sk_buff *skb, struct batman_if *recv_if); int recv_bcast_packet(struct sk_buff *skb); int recv_vis_packet(struct sk_buff *skb); int recv_bat_packet(struct sk_buff *skb,
Modified: trunk/batman-adv/soft-interface.c =================================================================== --- trunk/batman-adv/soft-interface.c 2010-07-11 14:34:10 UTC (rev 1736) +++ trunk/batman-adv/soft-interface.c 2010-07-11 14:34:12 UTC (rev 1737) @@ -32,6 +32,7 @@ #include <linux/ethtool.h> #include <linux/etherdevice.h> #include "compat.h" +#include "fragmentation.h"
static uint32_t bcast_seqno = 1; /* give own bcast messages seq numbers to avoid * broadcast storms */ @@ -130,6 +131,7 @@ int interface_tx(struct sk_buff *skb, struct net_device *dev) { struct unicast_packet *unicast_packet; + struct unicast_frag_packet *ucast_frag1, *ucast_frag2; struct bcast_packet *bcast_packet; struct orig_node *orig_node; struct neigh_node *router; @@ -137,9 +139,11 @@ struct bat_priv *priv = netdev_priv(dev); struct batman_if *batman_if; struct bat_priv *bat_priv; + struct sk_buff *frag_skb; uint8_t dstaddr[6]; int data_len = skb->len; unsigned long flags; + int hdr_len; bool bcast_dst = false, do_bcast = true;
if (atomic_read(&module_state) != MODULE_ACTIVE) @@ -216,20 +220,66 @@ if (batman_if->if_status != IF_ACTIVE) goto dropped;
- if (my_skb_push(skb, sizeof(struct unicast_packet)) < 0) - goto dropped; + if (atomic_read(&bat_priv->frag_enabled) && + data_len + sizeof(struct unicast_packet) > + batman_if->net_dev->mtu) {
- unicast_packet = (struct unicast_packet *)skb->data; + hdr_len = sizeof(struct unicast_frag_packet);
- unicast_packet->version = COMPAT_VERSION; - /* batman packet type: unicast */ - unicast_packet->packet_type = BAT_UNICAST; - /* set unicast ttl */ - unicast_packet->ttl = TTL; - /* copy the destination for faster routing */ - memcpy(unicast_packet->dest, orig_node->orig, ETH_ALEN); + frag_skb = dev_alloc_skb(data_len - (data_len / 2) + + hdr_len); + skb_split(skb, frag_skb, data_len / 2);
- send_skb_packet(skb, batman_if, dstaddr); + if (my_skb_push(frag_skb, hdr_len) < 0 || + my_skb_push(skb, hdr_len) < 0) { + + kfree_skb(frag_skb); + goto dropped; + } + + ucast_frag1 = (struct unicast_frag_packet *)skb->data; + ucast_frag2 = + (struct unicast_frag_packet *)frag_skb->data; + + ucast_frag1->version = COMPAT_VERSION; + ucast_frag1->packet_type = BAT_UNICAST_FRAG; + ucast_frag1->ttl = TTL; + memcpy(ucast_frag1->orig, + batman_if->net_dev->dev_addr, ETH_ALEN); + memcpy(ucast_frag1->dest, orig_node->orig, ETH_ALEN); + + memcpy(ucast_frag2, ucast_frag1, + sizeof(struct unicast_frag_packet)); + + ucast_frag1->flags |= UNI_FRAG_HEAD; + ucast_frag2->flags &= ~UNI_FRAG_HEAD; + + ucast_frag1->seqno = htons((uint16_t)atomic_inc_return( + &batman_if->frag_seqno)); + + ucast_frag2->seqno = htons((uint16_t)atomic_inc_return( + &batman_if->frag_seqno)); + + send_skb_packet(skb, batman_if, dstaddr); + send_skb_packet(frag_skb, batman_if, dstaddr); + + } else { + + if (my_skb_push(skb, sizeof(struct unicast_packet)) < 0) + goto dropped; + + unicast_packet = (struct unicast_packet *)skb->data; + + unicast_packet->version = COMPAT_VERSION; + /* batman packet type: unicast */ + unicast_packet->packet_type = BAT_UNICAST; + /* set unicast ttl */ + unicast_packet->ttl = TTL; + /* copy the destination for faster routing */ + memcpy(unicast_packet->dest, orig_node->orig, ETH_ALEN); + + send_skb_packet(skb, batman_if, dstaddr); + } }
priv->stats.tx_packets++; @@ -309,7 +359,9 @@ #endif dev->destructor = free_netdev;
- dev->mtu = hardif_min_mtu(); + dev->mtu = ETH_DATA_LEN; /* can't call min_mtu, because the + * needed variables have not been + * initialized yet */ dev->hard_header_len = BAT_HEADER_LEN; /* reserve more space in the * skbuff for our header */
Modified: trunk/batman-adv/types.h =================================================================== --- trunk/batman-adv/types.h 2010-07-11 14:34:10 UTC (rev 1736) +++ trunk/batman-adv/types.h 2010-07-11 14:34:12 UTC (rev 1737) @@ -41,6 +41,7 @@ char addr_str[ETH_STR_LEN]; struct net_device *net_dev; atomic_t seqno; + atomic_t frag_seqno; unsigned char *packet_buff; int packet_len; struct kobject *hardif_obj; @@ -82,6 +83,8 @@ TYPE_OF_WORD bcast_bits[NUM_WORDS]; uint32_t last_bcast_seqno; struct list_head neigh_list; + struct list_head frag_list; + unsigned long last_frag_packet; struct { uint8_t candidates; struct neigh_node *selected; @@ -118,6 +121,7 @@ struct net_device_stats stats; atomic_t aggregation_enabled; atomic_t bonding_enabled; + atomic_t frag_enabled; atomic_t vis_mode; atomic_t gw_mode; atomic_t gw_class; @@ -192,4 +196,10 @@ wait_queue_head_t queue_wait; };
+struct frag_packet_list_entry { + struct list_head list; + uint16_t seqno; + struct sk_buff *skb; +}; + #endif /* _NET_BATMAN_ADV_TYPES_H_ */