user/sven/linux.git/include/net/ip_tunnels.h, branch v5.18

ip_gre, ip6_gre: Fix race condition on o_seqno in collect_md mode

2022-04-25T10:40:45Z

As pointed out by Jakub Kicinski, currently using TUNNEL_SEQ in collect_md mode is racy for [IP6]GRE[TAP] devices. Consider the following sequence of events: 1. An [IP6]GRE[TAP] device is created in collect_md mode using "ip link add ... external". "ip" ignores "[o]seq" if "external" is specified, so TUNNEL_SEQ is off, and the device is marked as NETIF_F_LLTX (i.e. it uses lockless TX); 2. Someone sets TUNNEL_SEQ on outgoing skb's, using e.g. bpf_skb_set_tunnel_key() in an eBPF program attached to this device; 3. gre_fb_xmit() or __gre6_xmit() processes these skb's: gre_build_header(skb, tun_hlen, flags, protocol, tunnel_id_to_key32(tun_info->key.tun_id), (flags & TUNNEL_SEQ) ? htonl(tunnel->o_seqno++) : 0); ^^^^^^^^^^^^^^^^^ Since we are not using the TX lock (&txq->_xmit_lock), multiple CPUs may try to do this tunnel->o_seqno++ in parallel, which is racy. Fix it by making o_seqno atomic_t. As mentioned by Eric Dumazet in commit b790e01aee74 ("ip_gre: lockless xmit"), making o_seqno atomic_t increases "chance for packets being out of order at receiver" when NETIF_F_LLTX is on. Maybe a better fix would be: 1. Do not ignore "oseq" in external mode. Users MUST specify "oseq" if they want the kernel to allow sequencing of outgoing packets; 2. Reject all outgoing TUNNEL_SEQ packets if the device was not created with "oseq". Unfortunately, that would break userspace. We could now make [IP6]GRE[TAP] devices always NETIF_F_LLTX, but let us do it in separate patches to keep this fix minimal. Suggested-by: Jakub Kicinski Fixes: 77a5196a804e ("gre: add sequence number for collect md mode.") Signed-off-by: Peilin Ye Acked-by: William Tu Signed-off-by: David S. Miller

net: Handle l3mdev in ip_tunnel_init_flow

2022-04-15T21:27:30Z

Ido reported that the commit referenced in the Fixes tag broke a gre use case with dummy devices. Add a check to ip_tunnel_init_flow to see if the oif is an l3mdev port and if so set the oif to 0 to avoid the oif comparison in fib_lookup_good_nhc. Fixes: 40867d74c374 ("net: Add l3mdev index to flow struct and avoid oif reset for port devices") Reported-by: Ido Schimmel Signed-off-by: David Ahern Signed-off-by: Jakub Kicinski

sit: add net device refcount tracking to ip_tunnel

2021-12-07T00:05:11Z

Note that other ip_tunnel users do not seem to hold a reference on tunnel->dev. Probably needs some investigations. Signed-off-by: Eric Dumazet Signed-off-by: Jakub Kicinski

ip_tunnel: use ndo_siocdevprivate

2021-07-27T19:11:44Z

The various ipv4 and ipv6 tunnel drivers each implement a set of 12 SIOCDEVPRIVATE commands for managing tunnels. These all work correctly in compat mode. Move them over to the new .ndo_siocdevprivate operation. Cc: Hideaki YOSHIFUJI Cc: David Ahern Cc: Steffen Klassert Cc: Herbert Xu Signed-off-by: Arnd Bergmann Signed-off-by: David S. Miller

Merge https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2020-11-20T03:08:46Z

Signed-off-by: Jakub Kicinski

ip_tunnels: Set tunnel option flag when tunnel metadata is present

2020-11-14T00:58:10Z

Currently, we may set the tunnel option flag when the size of metadata is zero. For example, we set TUNNEL_GENEVE_OPT in the receive function no matter the geneve option is present or not. As this may result in issues on the tunnel flags consumers, this patch fixes the issue. Related discussion: * https://lore.kernel.org/netdev/1604448694-19351-1-git-send-email-yihung.wei@gmail.com/T/#u Fixes: 256c87c17c53 ("net: check tunnel option type in tunnel flags") Signed-off-by: Yi-Hung Wei Link: https://lore.kernel.org/r/1605053800-74072-1-git-send-email-yihung.wei@gmail.com Signed-off-by: Jakub Kicinski

net: remove ip_tunnel_get_stats64

2020-11-10T01:50:28Z

After having migrated all users remove ip_tunnel_get_stats64(). Signed-off-by: Heiner Kallweit Signed-off-by: Jakub Kicinski

tunnels: PMTU discovery support for directly bridged IP packets

2020-08-04T20:01:45Z

It's currently possible to bridge Ethernet tunnels carrying IP packets directly to external interfaces without assigning them addresses and routes on the bridged network itself: this is the case for UDP tunnels bridged with a standard bridge or by Open vSwitch. PMTU discovery is currently broken with those configurations, because the encapsulation effectively decreases the MTU of the link, and while we are able to account for this using PMTU discovery on the lower layer, we don't have a way to relay ICMP or ICMPv6 messages needed by the sender, because we don't have valid routes to it. On the other hand, as a tunnel endpoint, we can't fragment packets as a general approach: this is for instance clearly forbidden for VXLAN by RFC 7348, section 4.3: VTEPs MUST NOT fragment VXLAN packets. Intermediate routers may fragment encapsulated VXLAN packets due to the larger frame size. The destination VTEP MAY silently discard such VXLAN fragments. The same paragraph recommends that the MTU over the physical network accomodates for encapsulations, but this isn't a practical option for complex topologies, especially for typical Open vSwitch use cases. Further, it states that: Other techniques like Path MTU discovery (see [RFC1191] and [RFC1981]) MAY be used to address this requirement as well. Now, PMTU discovery already works for routed interfaces, we get route exceptions created by the encapsulation device as they receive ICMP Fragmentation Needed and ICMPv6 Packet Too Big messages, and we already rebuild those messages with the appropriate MTU and route them back to the sender. Add the missing bits for bridged cases: - checks in skb_tunnel_check_pmtu() to understand if it's appropriate to trigger a reply according to RFC 1122 section 3.2.2 for ICMP and RFC 4443 section 2.4 for ICMPv6. This function is already called by UDP tunnels - a new function generating those ICMP or ICMPv6 replies. We can't reuse icmp_send() and icmp6_send() as we don't see the sender as a valid destination. This doesn't need to be generic, as we don't cover any other type of ICMP errors given that we only provide an encapsulation function to the sender While at it, make the MTU check in skb_tunnel_check_pmtu() accurate: we might receive GSO buffers here, and the passed headroom already includes the inner MAC length, so we don't have to account for it a second time (that would imply three MAC headers on the wire, but there are just two). This issue became visible while bridging IPv6 packets with 4500 bytes of payload over GENEVE using IPv4 with a PMTU of 4000. Given the 50 bytes of encapsulation headroom, we would advertise MTU as 3950, and we would reject fragmented IPv6 datagrams of 3958 bytes size on the wire. We're exclusively dealing with network MTU here, though, so we could get Ethernet frames up to 3964 octets in that case. v2: - moved skb_tunnel_check_pmtu() to ip_tunnel_core.c (David Ahern) - split IPv4/IPv6 functions (David Ahern) Signed-off-by: Stefano Brivio Reviewed-by: David Ahern Signed-off-by: David S. Miller

net: ip_tunnel: add header_ops for layer 3 devices

2020-06-30T19:29:39Z

Some devices that take straight up layer 3 packets benefit from having a shared header_ops so that AF_PACKET sockets can inject packets that are recognized. This shared infrastructure will be used by other drivers that currently can't inject packets using AF_PACKET. It also exposes the parser function, as it is useful in standalone form too. Signed-off-by: Jason A. Donenfeld Acked-by: Willem de Bruijn Signed-off-by: David S. Miller

net: add a new ndo_tunnel_ioctl method

2020-05-19T22:45:11Z

This method is used to properly allow kernel callers of the IPv4 route management ioctls. The exsting ip_tunnel_ioctl helper is renamed to ip_tunnel_ctl to better reflect that it doesn't directly implement ioctls touching user memory, and is used for the guts of ndo_tunnel_ctl implementations. A new ip_tunnel_ioctl helper is added that can be wired up directly to the ndo_do_ioctl method and takes care of the copy to and from userspace. Signed-off-by: Christoph Hellwig Signed-off-by: David S. Miller