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RTNETLINK(3) | Linux Programmer's Manual | RTNETLINK(3) |
NAME¶
rtnetlink - Macros to manipuate rtnetlink messagesSYNOPSIS¶
#include <asm/types.h>DESCRIPTION¶
All rtnetlink(7) messages consist of a netlink(7) message header and appended attributes. The attributes should be only manipulated using the macros provided here. RTA_OK(rta, attrlen) returns true if rta points to a valid routing attribute; attrlen is the running length of the attribute buffer. When not true then you must assume there are no more attributes in the message, even if attrlen is non-zero.EXAMPLE¶
Creating a rtnetlink message to set a MTU of a device.struct { struct nlmsghdr nh; struct ifinfomsg if; char attrbuf[512]; } req; struct rtattr *rta; unsigned int mtu = 1000; int rtnetlink_sk = socket(PF_NETLINK, SOCK_DGRAM, NETLINK_ROUTE); memset(&req, 0, sizeof(req)); req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg)); req.nh.nlmsg_flags = NLM_F_REQUEST; req.nh.nlmsg_type = RTML_NEWLINK; req.if.ifi_family = AF_UNSPEC; req.if.ifi_index = INTERFACE_INDEX; req.if.ifi_change = 0xffffffff; /* ???*/ rta = (struct rtattr *)(((char *) &req) + NLMSG_ALIGN(n->nlmsg_len)); rta->rta_type = IFLA_MTU; rta->rta_len = sizeof(unsigned int); req.n.nlmsg_len = NLMSG_ALIGN(req.n.nlmsg_len) + RTA_LENGTH(sizeof(mtu)); memcpy(RTA_DATA(rta), &mtu, sizeof (mtu)); send(rtnetlink_sk, &req, req.n.nlmsg_len);
BUGS¶
This manual page is lacking and incomplete.SEE ALSO¶
rtnetlink(7), netlink(7), netlink(3)14 May 1999 | Linux Man Page |