diff options
Diffstat (limited to 'Documentation/networking')
-rw-r--r-- | Documentation/networking/ip-sysctl.txt | 9 | ||||
-rw-r--r-- | Documentation/networking/net-modules.txt | 6 | ||||
-rw-r--r-- | Documentation/networking/netdevices.txt | 38 |
3 files changed, 39 insertions, 14 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt index af6a63ab9026..32c2e9da5f3a 100644 --- a/Documentation/networking/ip-sysctl.txt +++ b/Documentation/networking/ip-sysctl.txt @@ -433,6 +433,12 @@ tcp_workaround_signed_windows - BOOLEAN not receive a window scaling option from them. Default: 0 +tcp_dma_copybreak - INTEGER + Lower limit, in bytes, of the size of socket reads that will be + offloaded to a DMA copy engine, if one is present in the system + and CONFIG_NET_DMA is enabled. + Default: 4096 + CIPSOv4 Variables: cipso_cache_enable - BOOLEAN @@ -874,8 +880,7 @@ accept_redirects - BOOLEAN accept_source_route - INTEGER Accept source routing (routing extension header). - > 0: Accept routing header. - = 0: Accept only routing header type 2. + >= 0: Accept only routing header type 2. < 0: Do not accept routing header. Default: 0 diff --git a/Documentation/networking/net-modules.txt b/Documentation/networking/net-modules.txt index 0b27863f155c..98c4392dd0fd 100644 --- a/Documentation/networking/net-modules.txt +++ b/Documentation/networking/net-modules.txt @@ -146,12 +146,6 @@ at1700.c: irq = 0 (Probes ports: 0x260, 0x280, 0x2A0, 0x240, 0x340, 0x320, 0x380, 0x300) -atari_bionet.c: - Supports full autoprobing. (m68k/Atari) - -atari_pamsnet.c: - Supports full autoprobing. (m68k/Atari) - atarilance.c: Supports full autoprobing. (m68k/Atari) diff --git a/Documentation/networking/netdevices.txt b/Documentation/networking/netdevices.txt index ce1361f95243..37869295fc70 100644 --- a/Documentation/networking/netdevices.txt +++ b/Documentation/networking/netdevices.txt @@ -20,6 +20,30 @@ private data which gets freed when the network device is freed. If separately allocated data is attached to the network device (dev->priv) then it is up to the module exit handler to free that. +MTU +=== +Each network device has a Maximum Transfer Unit. The MTU does not +include any link layer protocol overhead. Upper layer protocols must +not pass a socket buffer (skb) to a device to transmit with more data +than the mtu. The MTU does not include link layer header overhead, so +for example on Ethernet if the standard MTU is 1500 bytes used, the +actual skb will contain up to 1514 bytes because of the Ethernet +header. Devices should allow for the 4 byte VLAN header as well. + +Segmentation Offload (GSO, TSO) is an exception to this rule. The +upper layer protocol may pass a large socket buffer to the device +transmit routine, and the device will break that up into separate +packets based on the current MTU. + +MTU is symmetrical and applies both to receive and transmit. A device +must be able to receive at least the maximum size packet allowed by +the MTU. A network device may use the MTU as mechanism to size receive +buffers, but the device should allow packets with VLAN header. With +standard Ethernet mtu of 1500 bytes, the device should allow up to +1518 byte packets (1500 + 14 header + 4 tag). The device may either: +drop, truncate, or pass up oversize packets, but dropping oversize +packets is preferred. + struct net_device synchronization rules ======================================= @@ -43,16 +67,17 @@ dev->get_stats: dev->hard_start_xmit: Synchronization: netif_tx_lock spinlock. + When the driver sets NETIF_F_LLTX in dev->features this will be called without holding netif_tx_lock. In this case the driver has to lock by itself when needed. It is recommended to use a try lock - for this and return -1 when the spin lock fails. + for this and return NETDEV_TX_LOCKED when the spin lock fails. The locking there should also properly protect against - set_multicast_list - Context: Process with BHs disabled or BH (timer). - Notes: netif_queue_stopped() is guaranteed false - Interrupts must be enabled when calling hard_start_xmit. - (Interrupts must also be enabled when enabling the BH handler.) + set_multicast_list. + + Context: Process with BHs disabled or BH (timer), + will be called with interrupts disabled by netconsole. + Return codes: o NETDEV_TX_OK everything ok. o NETDEV_TX_BUSY Cannot transmit packet, try later @@ -74,4 +99,5 @@ dev->poll: Synchronization: __LINK_STATE_RX_SCHED bit in dev->state. See dev_close code and comments in net/core/dev.c for more info. Context: softirq + will be called with interrupts disabled by netconsole. |