netdev_alloc_skb(9) [centos man page]

NETDEV_ALLOC_SKB(9)						 Linux Networking					       NETDEV_ALLOC_SKB(9)

NAME

       netdev_alloc_skb - allocate an skbuff for rx on a specific device

SYNOPSIS

       struct sk_buff * netdev_alloc_skb(struct net_device * dev, unsigned int length);

ARGUMENTS

       dev
	   network device to receive on

       length
	   length to allocate

DESCRIPTION

       Allocate a new sk_buff and assign it a usage count of one. The buffer has unspecified headroom built in. Users should allocate the headroom
       they think they need without accounting for the built in space. The built in space is used for optimisations.

       NULL is returned if there is no free memory. Although this function allocates memory it can be called from an interrupt.

COPYRIGHT

Kernel Hackers Manual 3.10					     June 2014						       NETDEV_ALLOC_SKB(9)

__SKB_RECV_DATAGRAM(9)						 Linux Networking					    __SKB_RECV_DATAGRAM(9)

NAME

       __skb_recv_datagram - Receive a datagram skbuff

SYNOPSIS

       struct sk_buff * __skb_recv_datagram(struct sock * sk, unsigned int flags, int * peeked, int * off, int * err);

ARGUMENTS

       sk
	   socket

       flags
	   MSG_ flags

       peeked
	   returns non-zero if this packet has been seen before

       off
	   an offset in bytes to peek skb from. Returns an offset within an skb where data actually starts

       err
	   error code returned

DESCRIPTION

       Get a datagram skbuff, understands the peeking, nonblocking wakeups and possible races. This replaces identical code in packet, raw and
       udp, as well as the IPX AX.25 and Appletalk. It also finally fixes the long standing peek and read race for datagram sockets. If you alter
       this routine remember it must be re-entrant.

       This function will lock the socket if a skb is returned, so the caller needs to unlock the socket in that case (usually by calling
       skb_free_datagram)

       * It does not lock socket since today. This function is * free of race conditions. This measure should/can improve * significantly datagram
       socket latencies at high loads, * when data copying to user space takes lots of time. * (BTW I've just killed the last cli in
       IP/IPv6/core/netlink/packet * 8) Great win.) * --ANK (980729)

       The order of the tests when we find no data waiting are specified quite explicitly by POSIX 1003.1g, don't change them without having the
       standard around please.

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Kernel Hackers Manual 3.10					     June 2014						    __SKB_RECV_DATAGRAM(9)