NAME

udpread, udpwrite - read and write UDP packets

SYNOPSIS

#include <u.h>

#include <libc.h>

#include <ip.h>

typedef struct Udphdr Udphdr;
struct Udphdr
{
	uchar	raddr[IPaddrlen];	/* remote address and port */
	uchar	laddr[IPaddrlen];	/* local address and port */
	uchar	rport[2];
	uchar	lport[2];
};

long	udpread(int fd, Udphdr *hdr, void *data, long n)

long udpwrite(int fd, Udphdr *hdr, void *data, long n)

DESCRIPTION

Udpread and udpwrite read and write UDP packets from the UDP network connection established on file descriptor fd.

Udpread reads at most n bytes of packet body into data , stores the header in hdr, and returns the number of bytes stored in data.

Udpwrite writes the n bytes stored in data in a UDP packet with header hdr.

Note that the Udphdr frames the addresses as local and remote instead of source and destination. Thus the hdr filled in for a packet read by udpread can be used unchanged in udpwrite to send a response back to the sender of the original packet.

SOURCE

/src/lib9/udp.c

SEE ALSO