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bpf: xdp: Add XDP example for head adjustment

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The XDP prog checks if the incoming packet matches any VIP:PORT
combination in the BPF hashmap.  If it is, it will encapsulate
the packet with a IPv4/v6 header as instructed by the value of
the BPF hashmap and then XDP_TX it out.

The VIP:PORT -> IP-Encap-Info can be specified by the cmd args
of the user prog.

Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Martin KaFai Lau
2016-12-07 15:53:14 -08:00
committed by David S. Miller
parent ea3349a035
commit 12d8bb64e3
8 changed files with 630 additions and 93 deletions
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94
samples/bpf/bpf_load.c
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@@ -12,6 +12,10 @@
#include <linux/bpf.h>
#include <linux/filter.h>
#include <linux/perf_event.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/syscall.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
@@ -450,3 +454,93 @@ struct ksym *ksym_search(long key)
/* out of range. return _stext */
return &syms[0];
}
int set_link_xdp_fd(int ifindex, int fd)
{
struct sockaddr_nl sa;
int sock, seq = 0, len, ret = -1;
char buf[4096];
struct nlattr *nla, *nla_xdp;
struct {
struct nlmsghdr nh;
struct ifinfomsg ifinfo;
char attrbuf[64];
} req;
struct nlmsghdr *nh;
struct nlmsgerr *err;
memset(&sa, 0, sizeof(sa));
sa.nl_family = AF_NETLINK;
sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
if (sock < 0) {
printf("open netlink socket: %s\n", strerror(errno));
return -1;
}
if (bind(sock, (struct sockaddr *)&sa, sizeof(sa)) < 0) {
printf("bind to netlink: %s\n", strerror(errno));
goto cleanup;
}
memset(&req, 0, sizeof(req));
req.nh.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifinfomsg));
req.nh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK;
req.nh.nlmsg_type = RTM_SETLINK;
req.nh.nlmsg_pid = 0;
req.nh.nlmsg_seq = ++seq;
req.ifinfo.ifi_family = AF_UNSPEC;
req.ifinfo.ifi_index = ifindex;
nla = (struct nlattr *)(((char *)&req)
+ NLMSG_ALIGN(req.nh.nlmsg_len));
nla->nla_type = NLA_F_NESTED | 43/*IFLA_XDP*/;
nla_xdp = (struct nlattr *)((char *)nla + NLA_HDRLEN);
nla_xdp->nla_type = 1/*IFLA_XDP_FD*/;
nla_xdp->nla_len = NLA_HDRLEN + sizeof(int);
memcpy((char *)nla_xdp + NLA_HDRLEN, &fd, sizeof(fd));
nla->nla_len = NLA_HDRLEN + nla_xdp->nla_len;
req.nh.nlmsg_len += NLA_ALIGN(nla->nla_len);
if (send(sock, &req, req.nh.nlmsg_len, 0) < 0) {
printf("send to netlink: %s\n", strerror(errno));
goto cleanup;
}
len = recv(sock, buf, sizeof(buf), 0);
if (len < 0) {
printf("recv from netlink: %s\n", strerror(errno));
goto cleanup;
}
for (nh = (struct nlmsghdr *)buf; NLMSG_OK(nh, len);
nh = NLMSG_NEXT(nh, len)) {
if (nh->nlmsg_pid != getpid()) {
printf("Wrong pid %d, expected %d\n",
nh->nlmsg_pid, getpid());
goto cleanup;
}
if (nh->nlmsg_seq != seq) {
printf("Wrong seq %d, expected %d\n",
nh->nlmsg_seq, seq);
goto cleanup;
}
switch (nh->nlmsg_type) {
case NLMSG_ERROR:
err = (struct nlmsgerr *)NLMSG_DATA(nh);
if (!err->error)
continue;
printf("nlmsg error %s\n", strerror(-err->error));
goto cleanup;
case NLMSG_DONE:
break;
}
}
ret = 0;
cleanup:
close(sock);
return ret;
}