From e39376e4d5aa66a5f8973f4f5470c736afeab4ed Mon Sep 17 00:00:00 2001 From: Aloys Augustin 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 --- 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(-) 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 #include #include +#include #include #include @@ -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 1.2.3-korg