skb_copy_and_csum_datagram_iovec(9) [centos man page]
SKB_COPY_AND_CSUM_DA(9) Linux Networking SKB_COPY_AND_CSUM_DA(9)NAME
skb_copy_and_csum_datagram_iovec - Copy and checkum skb to user iovec.
SYNOPSIS
int skb_copy_and_csum_datagram_iovec(struct sk_buff * skb, int hlen, struct iovec * iov);
ARGUMENTS
skb
skbuff
hlen
hardware length
iov
io vector
DESCRIPTION
Caller _must_ check that skb will fit to this iovec.
RETURNS
0 - success. -EINVAL - checksum failure. -EFAULT - fault during copy. Beware, in this case iovec can be modified!
COPYRIGHT Kernel Hackers Manual 3.10 June 2014 SKB_COPY_AND_CSUM_DA(9)
Check Out this Related Man Page
READV(P) POSIX Programmer's Manual READV(P)
NAME
readv - read a vector
SYNOPSIS
#include <sys/uio.h>
ssize_t readv(int fildes, const struct iovec *iov, int iovcnt);
DESCRIPTION
The readv() function shall be equivalent to read(), except as described below. The readv() function shall place the input data into the
iovcnt buffers specified by the members of the iov array: iov[0], iov[1], ..., iov[ iovcnt-1]. The iovcnt argument is valid if greater
than 0 and less than or equal to {IOV_MAX}.
Each iovec entry specifies the base address and length of an area in memory where data should be placed. The readv() function shall always
fill an area completely before proceeding to the next.
Upon successful completion, readv() shall mark for update the st_atime field of the file.
RETURN VALUE
Refer to read() .
ERRORS
Refer to read() .
In addition, the readv() function shall fail if:
EINVAL The sum of the iov_len values in the iov array overflowed an ssize_t.
The readv() function may fail if:
EINVAL The iovcnt argument was less than or equal to 0, or greater than {IOV_MAX}.
The following sections are informative.
EXAMPLES
Reading Data into an Array
The following example reads data from the file associated with the file descriptor fd into the buffers specified by members of the iov
array.
#include <sys/types.h>
#include <sys/uio.h>
#include <unistd.h>
...
ssize_t bytes_read;
int fd;
char buf0[20];
char buf1[30];
char buf2[40];
int iovcnt;
struct iovec iov[3];
iov[0].iov_base = buf0;
iov[0].iov_len = sizeof(buf0);
iov[1].iov_base = buf1;
iov[1].iov_len = sizeof(buf1);
iov[2].iov_base = buf2;
iov[2].iov_len = sizeof(buf2);
...
iovcnt = sizeof(iov) / sizeof(struct iovec);
bytes_read = readv(fd, iov, iovcnt);
...
APPLICATION USAGE
None.
RATIONALE
Refer to read() .
FUTURE DIRECTIONS
None.
SEE ALSO
read() , writev() , the Base Definitions volume of IEEE Std 1003.1-2001, <sys/uio.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE
and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained
online at http://www.opengroup.org/unix/online.html .
IEEE /The Open Group 2003 READV(P)
Hi everyone,
I know the following questions are noobish questions but I am asking them because I am confused about the basics of history behind UNIX and LINUX.
Ok onto business, my questions are-:
Was/Is UNIX ever an open source operating system ?
If UNIX was... (21 Replies)
Hello and thanks in advance for any help anyone can offer me
I'm trying to learn the find command and thought I was understanding it... Apparently I was wrong. I was doing compound searches and I started getting weird results with the -size test. I was trying to do a search on a 1G file owned by... (14 Replies)
hi all,
i have installed quota on my centos 7 machine and its what im after (setting size limit on users, so they cant fill the hard drive)
i want to now make this part of my create user script for my sftp server so i want to do a echo and a read command so i capture the limit they enter... (0 Replies)
Hi everybody,
Which Unix base OS have best performance for HOST virtualization?
I tested SmartOS but it needs another OS to connect remotely!
Thanks in advance. (11 Replies)
Hi All,
I need to write a shell script which opens a file and increments the version(text) within the file every time the script runs. For example:
$ cat docker_file.yml
version: '3.1'
services:
ui:
image: repo-srv.dev.io:5000/facebook/ui:0.0.2-QA1
$
So, I would like... (6 Replies)
Dear Team
We use DB2 v10.5 and using DBArtisan tool
Can someone please guide how to convert digits to binary numbers using db2 feature.
Ex> for number 9 , binary should be 1001 ( 8+1)
Any help appreciated. Thanks (2 Replies)
hi folks,
how to using tar with exclude directory and compress it using tar.Z
i only know how to exclude dir only with this command below:
tar -cvf /varios/restore/test.tar -X excludefile.txt /jfma/test1/
how to compress it using 1 command?
Thanx
Please use CODE tags as... (6 Replies)
Quite an obscure question I think.
We have a rebuild process for remote sites that allows us to PXE rebuild a till (actually a PC with a touch screen and various fancy bits) running CentOS. The current CentOS5 tills work just fine with a tar image restore and some personalisation. Sadly,... (4 Replies)
Hello All,
I had recently learnt a bit of Docker(which provides containerization process).
Here are some of my learning points from it.
Let us start first with very basic question:
What is Docker:
Docker is a platform for sysadmins and developers to DEPLOY, DEVELOP and RUN applications ... (7 Replies)
What is the point of this? Whenever I close my shell it appends to the history file without adding this. I have never seen it overwrite my history file.
# When the shell exits, append to the history file instead of overwriting it
shopt -s histappend (3 Replies)
Hello... And thanks in advance for any help anyone can offer me
I was trying to work out the differences between displaying modify, access, and change times with the 'ls' command. Everything seems in order when I look at files, but the access time on a directory doesn't seem to change when I... (4 Replies)
Hello everyone,
I am having an issue here with CentOS release 6.6 (Final) that shows all of the space used up, but I can't tell where the space went.
Seemingly I am using up 100%, according to
df -h
Filesystem Size Used Avail Use% Mounted on... (27 Replies)
I'm trying to use a bash script for a psych experiment that involves listening to sound files and responding. If I have something like the code below, how can I make sure that a key press is assigned to RESPONSE only after the second echo statement?
for i in 1 2 3; do
echo "Ready?"
sleep 2
... (10 Replies)
After the success of the jq - tool for parsing and manipulating JSON-Data someone wrote a tool called yq, which aims to be the same for YAML, what jq is for JSON. Seems to work fine. I'll definitely give it a chance in future.
Example YAML-File:
--- !ruby/object:Puppet::Node::Facts
... (1 Reply)
Dear All,
I am very pleased to announce that Dave Munro (gull04) is joining the Moderation Team, after being a very valuable member of UNIX.com for 15+ years.
Dave is an IT Consultant with 30 years of experience this year, has worked in many of the industry vertical market segments and has... (6 Replies)