From 45d9b378e85f1b00ac047626827c68589168936c Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Sun, 30 Apr 2017 21:46:45 -0700 Subject: netlink: add NULL-friendly helper for setting extended ACK message As we propagate extended ack reporting throughout various paths in the kernel it may be that the same function is called with the extended ack parameter passed as NULL. One place where that happens is in drivers which have a centralized reconfiguration function called both from ndos and from ethtool_ops. Add a new helper for setting the error message in such conditions. Existing helper is left as is to encourage propagating the ext act fully wherever possible. It also makes it clear in the code which messages may be lost due to ext ack being NULL. Signed-off-by: Jakub Kicinski Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- include/linux/netlink.h | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'include') diff --git a/include/linux/netlink.h b/include/linux/netlink.h index 8d2a8924705c..c20395edf2de 100644 --- a/include/linux/netlink.h +++ b/include/linux/netlink.h @@ -92,6 +92,14 @@ struct netlink_ext_ack { (extack)->_msg = _msg; \ } while (0) +#define NL_MOD_TRY_SET_ERR_MSG(extack, msg) do { \ + static const char _msg[] = KBUILD_MODNAME ": " msg; \ + struct netlink_ext_ack *_extack = (extack); \ + \ + if (_extack) \ + _extack->_msg = _msg; \ +} while (0) + extern void netlink_kernel_release(struct sock *sk); extern int __netlink_change_ngroups(struct sock *sk, unsigned int groups); extern int netlink_change_ngroups(struct sock *sk, unsigned int groups); -- cgit v1.2.3 From ddf9f970764f4390aba767e77fddaaced4a6760d Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Sun, 30 Apr 2017 21:46:46 -0700 Subject: xdp: propagate extended ack to XDP setup Drivers usually have a number of restrictions for running XDP - most common being buffer sizes, LRO and number of rings. Even though some drivers try to be helpful and print error messages experience shows that users don't often consult kernel logs on netlink errors. Try to use the new extended ack mechanism to carry the message back to user space. Signed-off-by: Jakub Kicinski Acked-by: Daniel Borkmann Signed-off-by: David S. Miller --- include/linux/netdevice.h | 10 ++++++++-- net/core/dev.c | 5 ++++- net/core/rtnetlink.c | 13 ++++++++----- 3 files changed, 20 insertions(+), 8 deletions(-) (limited to 'include') diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index 6847714a5ae3..9c23bd2efb56 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -813,11 +813,16 @@ enum xdp_netdev_command { XDP_QUERY_PROG, }; +struct netlink_ext_ack; + struct netdev_xdp { enum xdp_netdev_command command; union { /* XDP_SETUP_PROG */ - struct bpf_prog *prog; + struct { + struct bpf_prog *prog; + struct netlink_ext_ack *extack; + }; /* XDP_QUERY_PROG */ bool prog_attached; }; @@ -3291,7 +3296,8 @@ int dev_get_phys_port_id(struct net_device *dev, int dev_get_phys_port_name(struct net_device *dev, char *name, size_t len); int dev_change_proto_down(struct net_device *dev, bool proto_down); -int dev_change_xdp_fd(struct net_device *dev, int fd, u32 flags); +int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack, + int fd, u32 flags); struct sk_buff *validate_xmit_skb_list(struct sk_buff *skb, struct net_device *dev); struct sk_buff *dev_hard_start_xmit(struct sk_buff *skb, struct net_device *dev, struct netdev_queue *txq, int *ret); diff --git a/net/core/dev.c b/net/core/dev.c index 8371a01eee87..35a06cebb282 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -6854,12 +6854,14 @@ EXPORT_SYMBOL(dev_change_proto_down); /** * dev_change_xdp_fd - set or clear a bpf program for a device rx path * @dev: device + * @extact: netlink extended ack * @fd: new program fd or negative value to clear * @flags: xdp-related flags * * Set or clear a bpf program for a device */ -int dev_change_xdp_fd(struct net_device *dev, int fd, u32 flags) +int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack, + int fd, u32 flags) { int (*xdp_op)(struct net_device *dev, struct netdev_xdp *xdp); const struct net_device_ops *ops = dev->netdev_ops; @@ -6892,6 +6894,7 @@ int dev_change_xdp_fd(struct net_device *dev, int fd, u32 flags) memset(&xdp, 0, sizeof(xdp)); xdp.command = XDP_SETUP_PROG; + xdp.extack = extack; xdp.prog = prog; err = xdp_op(dev, &xdp); diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 9031a6c8bfa7..6e67315ec368 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -1919,6 +1919,7 @@ static int do_set_master(struct net_device *dev, int ifindex) #define DO_SETLINK_NOTIFY 0x03 static int do_setlink(const struct sk_buff *skb, struct net_device *dev, struct ifinfomsg *ifm, + struct netlink_ext_ack *extack, struct nlattr **tb, char *ifname, int status) { const struct net_device_ops *ops = dev->netdev_ops; @@ -2201,7 +2202,7 @@ static int do_setlink(const struct sk_buff *skb, } if (xdp[IFLA_XDP_FD]) { - err = dev_change_xdp_fd(dev, + err = dev_change_xdp_fd(dev, extack, nla_get_s32(xdp[IFLA_XDP_FD]), xdp_flags); if (err) @@ -2261,7 +2262,7 @@ static int rtnl_setlink(struct sk_buff *skb, struct nlmsghdr *nlh, if (err < 0) goto errout; - err = do_setlink(skb, dev, ifm, tb, ifname, 0); + err = do_setlink(skb, dev, ifm, extack, tb, ifname, 0); errout: return err; } @@ -2423,6 +2424,7 @@ EXPORT_SYMBOL(rtnl_create_link); static int rtnl_group_changelink(const struct sk_buff *skb, struct net *net, int group, struct ifinfomsg *ifm, + struct netlink_ext_ack *extack, struct nlattr **tb) { struct net_device *dev, *aux; @@ -2430,7 +2432,7 @@ static int rtnl_group_changelink(const struct sk_buff *skb, for_each_netdev_safe(net, dev, aux) { if (dev->group == group) { - err = do_setlink(skb, dev, ifm, tb, NULL, 0); + err = do_setlink(skb, dev, ifm, extack, tb, NULL, 0); if (err < 0) return err; } @@ -2576,14 +2578,15 @@ replay: status |= DO_SETLINK_NOTIFY; } - return do_setlink(skb, dev, ifm, tb, ifname, status); + return do_setlink(skb, dev, ifm, extack, tb, ifname, + status); } if (!(nlh->nlmsg_flags & NLM_F_CREATE)) { if (ifm->ifi_index == 0 && tb[IFLA_GROUP]) return rtnl_group_changelink(skb, net, nla_get_u32(tb[IFLA_GROUP]), - ifm, tb); + ifm, extack, tb); return -ENODEV; } -- cgit v1.2.3