user/sven/linux.git/include/uapi/linux/in.h, branch v5.10.74

icmp: don't send out ICMP messages with a source address of 0.0.0.0

2021-06-23T12:42:47Z

[ Upstream commit 321827477360934dc040e9d3c626bf1de6c3ab3c ] When constructing ICMP response messages, the kernel will try to pick a suitable source address for the outgoing packet. However, if no IPv4 addresses are configured on the system at all, this will fail and we end up producing an ICMP message with a source address of 0.0.0.0. This can happen on a box routing IPv4 traffic via v6 nexthops, for instance. Since 0.0.0.0 is not generally routable on the internet, there's a good chance that such ICMP messages will never make it back to the sender of the original packet that the ICMP message was sent in response to. This, in turn, can create connectivity and PMTUd problems for senders. Fortunately, RFC7600 reserves a dummy address to be used as a source for ICMP messages (192.0.0.8/32), so let's teach the kernel to substitute that address as a last resort if the regular source address selection procedure fails. Below is a quick example reproducing this issue with network namespaces: ip netns add ns0 ip l add type veth peer netns ns0 ip l set dev veth0 up ip a add 10.0.0.1/24 dev veth0 ip a add fc00:dead:cafe:42::1/64 dev veth0 ip r add 10.1.0.0/24 via inet6 fc00:dead:cafe:42::2 ip -n ns0 l set dev veth0 up ip -n ns0 a add fc00:dead:cafe:42::2/64 dev veth0 ip -n ns0 r add 10.0.0.0/24 via inet6 fc00:dead:cafe:42::1 ip netns exec ns0 sysctl -w net.ipv4.icmp_ratelimit=0 ip netns exec ns0 sysctl -w net.ipv4.ip_forward=1 tcpdump -tpni veth0 -c 2 icmp & ping -w 1 10.1.0.1 > /dev/null tcpdump: verbose output suppressed, use -v[v]... for full protocol decode listening on veth0, link-type EN10MB (Ethernet), snapshot length 262144 bytes IP 10.0.0.1 > 10.1.0.1: ICMP echo request, id 29, seq 1, length 64 IP 0.0.0.0 > 10.0.0.1: ICMP net 10.1.0.1 unreachable, length 92 2 packets captured 2 packets received by filter 0 packets dropped by kernel With this patch the above capture changes to: IP 10.0.0.1 > 10.1.0.1: ICMP echo request, id 31127, seq 1, length 64 IP 192.0.0.8 > 10.0.0.1: ICMP net 10.1.0.1 unreachable, length 92 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: Juliusz Chroboczek Reviewed-by: David Ahern Signed-off-by: Toke Høiland-Jørgensen Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net: Fix some comments

2020-08-27T14:55:59Z

Fix some comments, including wrong function name, duplicated word and so on. Signed-off-by: Miaohe Lin Signed-off-by: David S. Miller

icmp: support rfc 4884

2020-07-20T02:20:22Z

Add setsockopt SOL_IP/IP_RECVERR_4884 to return the offset to an extension struct if present. ICMP messages may include an extension structure after the original datagram. RFC 4884 standardized this behavior. It stores the offset in words to the extension header in u8 icmphdr.un.reserved[1]. The field is valid only for ICMP types destination unreachable, time exceeded and parameter problem, if length is at least 128 bytes and entire packet does not exceed 576 bytes. Return the offset to the start of the extension struct when reading an ICMP error from the error queue, if it matches the above constraints. Do not return the raw u8 field. Return the offset from the start of the user buffer, in bytes. The kernel does not return the network and transport headers, so subtract those. Also validate the headers. Return the offset regardless of validation, as an invalid extension must still not be misinterpreted as part of the original datagram. Note that !invalid does not imply valid. If the extension version does not match, no validation can take place, for instance. For backward compatibility, make this optional, set by setsockopt SOL_IP/IP_RECVERR_RFC4884. For API example and feature test, see github.com/wdebruij/kerneltools/blob/master/tests/recv_icmp_v2.c For forward compatibility, reserve only setsockopt value 1, leaving other bits for additional icmp extensions. Changes v1->v2: - convert word offset to byte offset from start of user buffer - return in ee_data as u8 may be insufficient - define extension struct and object header structs - return len only if constraints met - if returning len, also validate Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller

seg6: fix SRv6 L2 tunnels to use IANA-assigned protocol number

2020-03-12T06:49:30Z

The Internet Assigned Numbers Authority (IANA) has recently assigned a protocol number value of 143 for Ethernet [1]. Before this assignment, encapsulation mechanisms such as Segment Routing used the IPv6-NoNxt protocol number (59) to indicate that the encapsulated payload is an Ethernet frame. In this patch, we add the definition of the Ethernet protocol number to the kernel headers and update the SRv6 L2 tunnels to use it. [1] https://www.iana.org/assignments/protocol-numbers/protocol-numbers.xhtml Signed-off-by: Paolo Lungaroni Reviewed-by: Andrea Mayer Acked-by: Ahmed Abdelsalam Signed-off-by: David S. Miller

tcp: Define IPPROTO_MPTCP

2020-01-10T02:41:41Z

To open a MPTCP socket with socket(AF_INET, SOCK_STREAM, IPPROTO_MPTCP), IPPROTO_MPTCP needs a value that differs from IPPROTO_TCP. The existing IPPROTO numbers mostly map directly to IANA-specified protocol numbers. MPTCP does not have a protocol number allocated because MPTCP packets use the TCP protocol number. Use private number not used OTA. Reviewed-by: Eric Dumazet Signed-off-by: Mat Martineau Signed-off-by: David S. Miller

bridge: join all-snoopers multicast address

2019-01-23T01:18:08Z

Next to snooping IGMP/MLD queries RFC4541, section 2.1.1.a) recommends to snoop multicast router advertisements to detect multicast routers. Multicast router advertisements are sent to an "all-snoopers" multicast address. To be able to receive them reliably, we need to join this group. Otherwise other snooping switches might refrain from forwarding these advertisements to us. Signed-off-by: Linus Lüssing Signed-off-by: David S. Miller

IN_BADCLASS: fix macro to actually work

2019-01-16T05:45:21Z

Commit 65cab850f0ee ("net: Allow class-e address assignment via ifconfig ioctl") modified the IN_BADCLASS macro a bit, but unfortunatly one too many '(' characters were added to the line, making any code that used it, not build properly. Also, the macro now compares an unsigned with a signed value, which isn't ok, so fix that up by making both types match properly. Reported-by: Christopher Ferris Fixes: 65cab850f0ee ("net: Allow class-e address assignment via ifconfig ioctl") Cc: Dave Taht Signed-off-by: Greg Kroah-Hartman Signed-off-by: David S. Miller

net: Allow class-e address assignment via ifconfig ioctl

2018-12-14T23:39:31Z

While most distributions long ago switched to the iproute2 suite of utilities, which allow class-e (240.0.0.0/4) address assignment, distributions relying on busybox, toybox and other forms of ifconfig cannot assign class-e addresses without this kernel patch. While CIDR has been obsolete for 2 decades, and a survey of all the open source code in the world shows the IN_whatever macros are also obsolete... rather than obsolete CIDR from this ioctl entirely, this patch merely enables class-e assignment, sanely. Signed-off-by: Dave Taht Signed-off-by: David S. Miller

License cleanup: add SPDX license identifier to uapi header files with a license

2017-11-02T10:20:11Z

Many user space API headers have licensing information, which is either incomplete, badly formatted or just a shorthand for referring to the license under which the file is supposed to be. This makes it hard for compliance tools to determine the correct license. Update these files with an SPDX license identifier. The identifier was chosen based on the license information in the file. GPL/LGPL licensed headers get the matching GPL/LGPL SPDX license identifier with the added 'WITH Linux-syscall-note' exception, which is the officially assigned exception identifier for the kernel syscall exception: NOTE! This copyright does *not* cover user programs that use kernel services by normal system calls - this is merely considered normal use of the kernel, and does *not* fall under the heading of "derived work". This exception makes it possible to include GPL headers into non GPL code, without confusing license compliance tools. Headers which have either explicit dual licensing or are just licensed under a non GPL license are updated with the corresponding SPDX identifier and the GPLv2 with syscall exception identifier. The format is: ((GPL-2.0 WITH Linux-syscall-note) OR SPDX-ID-OF-OTHER-LICENSE) SPDX license identifiers are a legally binding shorthand, which can be used instead of the full boiler plate text. The update does not remove existing license information as this has to be done on a case by case basis and the copyright holders might have to be consulted. This will happen in a separate step. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. See the previous patch in this series for the methodology of how this patch was researched. Reviewed-by: Kate Stewart Reviewed-by: Philippe Ombredanne Reviewed-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

ipv4: add IP_RECVFRAGSIZE cmsg

2016-11-03T19:41:11Z

The IP stack records the largest fragment of a reassembled packet in IPCB(skb)->frag_max_size. When reading a datagram or raw packet that arrived fragmented, expose the value to allow applications to estimate receive path MTU. Tested: Sent data over a veth pair of which the source has a small mtu. Sent data using netcat, received using a dedicated process. Verified that the cmsg IP_RECVFRAGSIZE is returned only when data arrives fragmented, and in that cases matches the veth mtu. ip link add veth0 type veth peer name veth1 ip netns add from ip netns add to ip link set dev veth1 netns to ip netns exec to ip addr add dev veth1 192.168.10.1/24 ip netns exec to ip link set dev veth1 up ip link set dev veth0 netns from ip netns exec from ip addr add dev veth0 192.168.10.2/24 ip netns exec from ip link set dev veth0 up ip netns exec from ip link set dev veth0 mtu 1300 ip netns exec from ethtool -K veth0 ufo off dd if=/dev/zero bs=1 count=1400 2>/dev/null > payload ip netns exec to ./recv_cmsg_recvfragsize -4 -u -p 6000 & ip netns exec from nc -q 1 -u 192.168.10.1 6000 < payload using github.com/wdebruij/kerneltools/blob/master/tests/recvfragsize.c Signed-off-by: Willem de Bruijn Acked-by: Eric Dumazet Signed-off-by: David S. Miller