From e39376e4d5aa66a5f8973f4f5470c736afeab4ed Mon Sep 17 00:00:00 2001
From: Aloys Augustin <aloaugus@cisco.com>
Date: Mon, 29 Mar 2021 22:08:09 +0200
Subject: devices: af_packet - use netlink to get/set mtu
The /sys filesystem is not always accurate when switching network
namespaces. Using netlink should work in more situations.
Type: improvement
Change-Id: I71611f14319820469ea7794eec5b7c6c70e2be6d
Signed-off-by: Aloys Augustin <aloaugus@cisco.com>
---
src/vnet/devices/af_packet/af_packet.c | 18 ++----
src/vnet/devices/netlink.c | 104 +++++++++++++++++++++++++++++----
src/vnet/devices/netlink.h | 1 +
3 files changed, 100 insertions(+), 23 deletions(-)
(limited to 'src')
diff --git a/src/vnet/devices/af_packet/af_packet.c b/src/vnet/devices/af_packet/af_packet.c
index 60a3ccc081f..76677a43092 100644
--- a/src/vnet/devices/af_packet/af_packet.c
+++ b/src/vnet/devices/af_packet/af_packet.c
@@ -30,6 +30,7 @@
#include <vlib/vlib.h>
#include <vlib/unix/unix.h>
#include <vnet/ip/ip.h>
+#include <vnet/devices/netlink.h>
#include <vnet/ethernet/ethernet.h>
#include <vnet/interface/rx_queue_funcs.h>
@@ -63,22 +64,18 @@ af_packet_eth_flag_change (vnet_main_t * vnm, vnet_hw_interface_t * hi,
u32 flags)
{
clib_error_t *error;
- u8 *s;
af_packet_main_t *apm = &af_packet_main;
af_packet_if_t *apif =
pool_elt_at_index (apm->interfaces, hi->dev_instance);
if (flags == ETHERNET_INTERFACE_FLAG_MTU)
{
- s = format (0, "/sys/class/net/%s/mtu%c", apif->host_if_name, 0);
-
- error = clib_sysfs_write ((char *) s, "%d", hi->max_packet_bytes);
- vec_free (s);
+ error =
+ vnet_netlink_set_link_mtu (apif->host_if_index, hi->max_packet_bytes);
if (error)
{
- vlib_log_err (apm->log_class,
- "sysfs write failed to change MTU: %U",
+ vlib_log_err (apm->log_class, "netlink failed to change MTU: %U",
format_clib_error, error);
clib_error_free (error);
return VNET_API_ERROR_SYSCALL_ERROR_1;
@@ -95,13 +92,10 @@ af_packet_read_mtu (af_packet_if_t *apif)
{
af_packet_main_t *apm = &af_packet_main;
clib_error_t *error;
- u8 *s;
- s = format (0, "/sys/class/net/%s/mtu%c", apif->host_if_name, 0);
- error = clib_sysfs_read ((char *) s, "%d", &apif->host_mtu);
- vec_free (s);
+ error = vnet_netlink_get_link_mtu (apif->host_if_index, &apif->host_mtu);
if (error)
{
- vlib_log_err (apm->log_class, "sysfs read failed to get MTU: %U",
+ vlib_log_err (apm->log_class, "netlink failed to get MTU: %U",
format_clib_error, error);
clib_error_free (error);
return VNET_API_ERROR_SYSCALL_ERROR_1;
diff --git a/src/vnet/devices/netlink.c b/src/vnet/devices/netlink.c
index 34309e1b916..9aae205c54f 100644
--- a/src/vnet/devices/netlink.c
+++ b/src/vnet/devices/netlink.c
@@ -63,7 +63,7 @@ vnet_netlink_msg_add_rtattr (vnet_netlink_msg_t * m, u16 rta_type,
}
static clib_error_t *
-vnet_netlink_msg_send (vnet_netlink_msg_t * m)
+vnet_netlink_msg_send (vnet_netlink_msg_t *m, vnet_netlink_msg_t **replies)
{
clib_error_t *err = 0;
struct sockaddr_nl ra = { 0 };
@@ -103,6 +103,15 @@ vnet_netlink_msg_send (vnet_netlink_msg_t * m)
err = clib_error_return (0, "netlink error %d", e->error);
goto done;
}
+
+ if (replies)
+ {
+ vnet_netlink_msg_t msg = { NULL };
+ u8 *p;
+ vec_add2 (msg.data, p, nh->nlmsg_len);
+ clib_memcpy (p, nh, nh->nlmsg_len);
+ vec_add1 (*replies, msg);
+ }
}
done:
@@ -125,7 +134,7 @@ vnet_netlink_set_link_name (int ifindex, char *new_ifname)
vnet_netlink_msg_add_rtattr (&m, IFLA_IFNAME, new_ifname,
strlen (new_ifname) + 1);
- err = vnet_netlink_msg_send (&m);
+ err = vnet_netlink_msg_send (&m, NULL);
if (err)
err = clib_error_return (0, "set link name %U", format_clib_error, err);
return err;
@@ -147,7 +156,7 @@ vnet_netlink_set_link_netns (int ifindex, int netns_fd, char *new_ifname)
vnet_netlink_msg_add_rtattr (&m, IFLA_IFNAME, new_ifname,
strlen (new_ifname) + 1);
- err = vnet_netlink_msg_send (&m);
+ err = vnet_netlink_msg_send (&m, NULL);
if (err)
err = clib_error_return (0, "set link netns %U", format_clib_error, err);
return err;
@@ -170,7 +179,7 @@ vnet_netlink_set_link_master (int ifindex, char *master_ifname)
vnet_netlink_msg_init (&m, RTM_SETLINK, NLM_F_REQUEST,
&ifmsg, sizeof (struct ifinfomsg));
vnet_netlink_msg_add_rtattr (&m, IFLA_MASTER, &i, sizeof (int));
- err = vnet_netlink_msg_send (&m);
+ err = vnet_netlink_msg_send (&m, NULL);
if (err)
err = clib_error_return (0, "set link master %U", format_clib_error, err);
return err;
@@ -188,7 +197,7 @@ vnet_netlink_set_link_addr (int ifindex, u8 * mac)
vnet_netlink_msg_init (&m, RTM_SETLINK, NLM_F_REQUEST,
&ifmsg, sizeof (struct ifinfomsg));
vnet_netlink_msg_add_rtattr (&m, IFLA_ADDRESS, mac, 6);
- err = vnet_netlink_msg_send (&m);
+ err = vnet_netlink_msg_send (&m, NULL);
if (err)
err = clib_error_return (0, "set link addr %U", format_clib_error, err);
return err;
@@ -207,12 +216,85 @@ vnet_netlink_set_link_state (int ifindex, int up)
vnet_netlink_msg_init (&m, RTM_SETLINK, NLM_F_REQUEST,
&ifmsg, sizeof (struct ifinfomsg));
- err = vnet_netlink_msg_send (&m);
+ err = vnet_netlink_msg_send (&m, NULL);
if (err)
err = clib_error_return (0, "set link state %U", format_clib_error, err);
return err;
}
+clib_error_t *
+vnet_netlink_get_link_mtu (int ifindex, u32 *mtu)
+{
+ vnet_netlink_msg_t m, *msg;
+ struct ifinfomsg ifmsg = { 0 };
+ struct nlattr *attr;
+ clib_error_t *err = 0;
+ vnet_netlink_msg_t *replies = NULL;
+ int len = 0, offset = 0;
+ u32 msg_mtu;
+
+ ifmsg.ifi_index = ifindex;
+
+ vnet_netlink_msg_init (&m, RTM_GETLINK, NLM_F_REQUEST, &ifmsg,
+ sizeof (struct ifinfomsg));
+ // vnet_netlink_msg_add_rtattr (&m, IFLA_MTU, &mtu, sizeof (int));
+ err = vnet_netlink_msg_send (&m, &replies);
+ if (err)
+ {
+ err = clib_error_return (0, "get link mtu %U", format_clib_error, err);
+ goto done;
+ }
+
+ if (vec_len (replies) != 1)
+ {
+ err = clib_error_return (0, "got %d != 1 netlink reply msg",
+ vec_len (replies));
+ goto done;
+ }
+
+ struct nlmsghdr *nh = (struct nlmsghdr *) replies[0].data;
+ if (nh->nlmsg_type != RTM_NEWLINK)
+ {
+ err = clib_error_return (
+ 0, "netlink reply has wrong type: %d != RTM_NEWLINK", nh->nlmsg_type);
+ goto done;
+ }
+
+ offset = NLMSG_HDRLEN + NLMSG_ALIGN (sizeof (struct ifinfomsg));
+ attr = (struct nlattr *) ((u8 *) nh + offset);
+ len = nh->nlmsg_len - offset;
+
+ do
+ {
+ if ((attr->nla_type & NLA_TYPE_MASK) == IFLA_MTU)
+ {
+ msg_mtu = *(u32 *) ((u8 *) attr + NLA_HDRLEN);
+ if (attr->nla_type & NLA_F_NET_BYTEORDER)
+ *mtu = clib_net_to_host_u32 (msg_mtu);
+ else
+ *mtu = msg_mtu;
+ clib_warning ("mtu: %d", *mtu);
+ goto done;
+ }
+ offset = NLA_ALIGN (attr->nla_len);
+ len -= offset;
+ attr = (struct nlattr *) ((u8 *) attr + offset);
+ }
+ while (len > sizeof (struct nlattr));
+
+ /* not found */
+ err = clib_error_return (0, "mtu not found in netlink message");
+
+done:
+ vec_foreach (msg, replies)
+ {
+ vec_free (msg->data);
+ }
+ vec_free (replies);
+
+ return err;
+}
+
clib_error_t *
vnet_netlink_set_link_mtu (int ifindex, int mtu)
{
@@ -225,7 +307,7 @@ vnet_netlink_set_link_mtu (int ifindex, int mtu)
vnet_netlink_msg_init (&m, RTM_SETLINK, NLM_F_REQUEST,
&ifmsg, sizeof (struct ifinfomsg));
vnet_netlink_msg_add_rtattr (&m, IFLA_MTU, &mtu, sizeof (int));
- err = vnet_netlink_msg_send (&m);
+ err = vnet_netlink_msg_send (&m, NULL);
if (err)
err = clib_error_return (0, "set link mtu %U", format_clib_error, err);
return err;
@@ -248,7 +330,7 @@ vnet_netlink_add_ip4_addr (int ifindex, void *addr, int pfx_len)
vnet_netlink_msg_add_rtattr (&m, IFA_LOCAL, addr, 4);
vnet_netlink_msg_add_rtattr (&m, IFA_ADDRESS, addr, 4);
- err = vnet_netlink_msg_send (&m);
+ err = vnet_netlink_msg_send (&m, NULL);
if (err)
err = clib_error_return (0, "add ip4 addr %U", format_clib_error, err);
return err;
@@ -271,7 +353,7 @@ vnet_netlink_add_ip6_addr (int ifindex, void *addr, int pfx_len)
vnet_netlink_msg_add_rtattr (&m, IFA_LOCAL, addr, 16);
vnet_netlink_msg_add_rtattr (&m, IFA_ADDRESS, addr, 16);
- err = vnet_netlink_msg_send (&m);
+ err = vnet_netlink_msg_send (&m, NULL);
if (err)
err = clib_error_return (0, "add ip6 addr %U", format_clib_error, err);
return err;
@@ -296,7 +378,7 @@ vnet_netlink_add_ip4_route (void *dst, u8 dst_len, void *gw)
vnet_netlink_msg_add_rtattr (&m, RTA_GATEWAY, gw, 4);
vnet_netlink_msg_add_rtattr (&m, RTA_DST, dst ? dst : dflt, 4);
- err = vnet_netlink_msg_send (&m);
+ err = vnet_netlink_msg_send (&m, NULL);
if (err)
err = clib_error_return (0, "add ip4 route %U", format_clib_error, err);
return err;
@@ -321,7 +403,7 @@ vnet_netlink_add_ip6_route (void *dst, u8 dst_len, void *gw)
vnet_netlink_msg_add_rtattr (&m, RTA_GATEWAY, gw, 16);
vnet_netlink_msg_add_rtattr (&m, RTA_DST, dst ? dst : dflt, 16);
- err = vnet_netlink_msg_send (&m);
+ err = vnet_netlink_msg_send (&m, NULL);
if (err)
err = clib_error_return (0, "add ip6 route %U", format_clib_error, err);
return err;
diff --git a/src/vnet/devices/netlink.h b/src/vnet/devices/netlink.h
index 4c765685091..f1c42609cbf 100644
--- a/src/vnet/devices/netlink.h
+++ b/src/vnet/devices/netlink.h
@@ -22,6 +22,7 @@ clib_error_t *vnet_netlink_set_link_netns (int ifindex, int netns_fd,
clib_error_t *vnet_netlink_set_link_master (int ifindex, char *master_ifname);
clib_error_t *vnet_netlink_set_link_addr (int ifindex, u8 * addr);
clib_error_t *vnet_netlink_set_link_state (int ifindex, int up);
+clib_error_t *vnet_netlink_get_link_mtu (int ifindex, u32 *mtu);
clib_error_t *vnet_netlink_set_link_mtu (int ifindex, int mtu);
clib_error_t *vnet_netlink_add_ip4_addr (int ifindex, void *addr,
int pfx_len);
--
cgit