skb_copy(9) [suse man page]

SKB_COPY(9)							 Linux Networking						       SKB_COPY(9)

NAME

       skb_copy - create private copy of an sk_buff

SYNOPSIS

       struct sk_buff * skb_copy(const struct sk_buff * skb, gfp_t gfp_mask);

ARGUMENTS

       skb
	   buffer to copy

       gfp_mask
	   allocation priority

DESCRIPTION

       Make a copy of both an sk_buff and its data. This is used when the caller wishes to modify the data and needs a private copy of the data to
       alter. Returns NULL on failure or the pointer to the buffer on success. The returned buffer has a reference count of 1.

       As by-product this function converts non-linear sk_buff to linear one, so that sk_buff becomes completely private and caller is allowed to
       modify all the data of returned buffer. This means that this function is not recommended for use in circumstances when only header is going
       to be modified. Use pskb_copy instead.

COPYRIGHT

Kernel Hackers Manual 2.6.					     July 2010							       SKB_COPY(9)

STRUCT 
SK_BUFF(9)						 Linux Networking						 STRUCT SK_BUFF(9)

NAME

       struct_sk_buff - socket buffer

SYNOPSIS

       struct sk_buff {
	 struct sk_buff * next;
	 struct sk_buff * prev;
	 ktime_t tstamp;
	 struct sock * sk;
	 struct net_device * dev;
	 char cb[48];
	 unsigned long _skb_refdst;
       #ifdef CONFIG_XFRM
	 struct sec_path * sp;
       #endif
	 unsigned int len;
	 unsigned int data_len;
	 __u16 mac_len;
	 __u16 hdr_len;
	 union {unnamed_union};
	 __be16 inner_protocol;
	 __u16 inner_transport_header;
	 __u16 inner_network_header;
	 __u16 inner_mac_header;
	 __u16 transport_header;
	 __u16 network_header;
	 __u16 mac_header;
	 sk_buff_data_t tail;
	 sk_buff_data_t end;
	 unsigned char * head;
	 unsigned char * data;
	 unsigned int truesize;
	 atomic_t users;
       };

MEMBERS

       next
	   Next buffer in list

       prev
	   Previous buffer in list

       tstamp
	   Time we arrived

       sk
	   Socket we are owned by

       dev
	   Device we arrived on/are leaving by

       cb[48]
	   Control buffer. Free for use by every layer. Put private vars here

       _skb_refdst
	   destination entry (with norefcount bit)

       sp
	   the security path, used for xfrm

       len
	   Length of actual data

       data_len
	   Data length

       mac_len
	   Length of link layer header

       hdr_len
	   writable header length of cloned skb

       {unnamed_union}
	   anonymous

       inner_protocol
	   Protocol (encapsulation)

       inner_transport_header
	   Inner transport layer header (encapsulation)

       inner_network_header
	   Network layer header (encapsulation)

       inner_mac_header
	   Link layer header (encapsulation)

       transport_header
	   Transport layer header

       network_header
	   Network layer header

       mac_header
	   Link layer header

       tail
	   Tail pointer

       end
	   End pointer

       head
	   Head of buffer

       data
	   Data head pointer

       truesize
	   Buffer size

       users
	   User count - see {datagram,tcp}.c

COPYRIGHT

Kernel Hackers Manual 3.10					     June 2014							 STRUCT SK_BUFF(9)