diff options
| author | Ido Schimmel <idosch@nvidia.com> | 2025-10-27 11:22:30 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-10-30 04:28:29 +0300 |
| commit | f0e7036fc9cb08bdfb27d64eee7fc003ba0bc2e5 (patch) | |
| tree | ed005f7a3fde423fc25efa532b0b43241d95096e /include | |
| parent | b8a7826e4b1aab3fabb29cbf0b73da9993d356de (diff) | |
| download | linux-f0e7036fc9cb08bdfb27d64eee7fc003ba0bc2e5.tar.xz | |
ipv4: icmp: Add RFC 5837 support
Add the ability to append the incoming IP interface information to
ICMPv4 error messages in accordance with RFC 5837 and RFC 4884. This is
required for more meaningful traceroute results in unnumbered networks.
The feature is disabled by default and controlled via a new sysctl
("net.ipv4.icmp_errors_extension_mask") which accepts a bitmask of ICMP
extensions to append to ICMP error messages. Currently, only a single
value is supported, but the interface and the implementation should be
able to support more extensions, if needed.
Clone the skb and copy the relevant data portions before modifying the
skb as the caller of __icmp_send() still owns the skb after the function
returns. This should be fine since by default ICMP error messages are
rate limited to 1000 per second and no more than 1 per second per
specific host.
Trim or pad the packet to 128 bytes before appending the ICMP extension
structure in order to be compatible with legacy applications that assume
that the ICMP extension structure always starts at this offset (the
minimum length specified by RFC 4884).
Reviewed-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20251027082232.232571-2-idosch@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/icmp.h | 32 | ||||
| -rw-r--r-- | include/net/netns/ipv4.h | 1 |
2 files changed, 33 insertions, 0 deletions
diff --git a/include/linux/icmp.h b/include/linux/icmp.h index 0af4d210ee31..043ec5d9c882 100644 --- a/include/linux/icmp.h +++ b/include/linux/icmp.h @@ -40,4 +40,36 @@ void ip_icmp_error_rfc4884(const struct sk_buff *skb, struct sock_ee_data_rfc4884 *out, int thlen, int off); +/* RFC 4884 */ +#define ICMP_EXT_ORIG_DGRAM_MIN_LEN 128 +#define ICMP_EXT_VERSION_2 2 + +/* ICMP Extension Object Classes */ +#define ICMP_EXT_OBJ_CLASS_IIO 2 /* RFC 5837 */ + +/* Interface Information Object - RFC 5837 */ +enum { + ICMP_EXT_CTYPE_IIO_ROLE_IIF, +}; + +#define ICMP_EXT_CTYPE_IIO_ROLE(ROLE) ((ROLE) << 6) +#define ICMP_EXT_CTYPE_IIO_MTU BIT(0) +#define ICMP_EXT_CTYPE_IIO_NAME BIT(1) +#define ICMP_EXT_CTYPE_IIO_IPADDR BIT(2) +#define ICMP_EXT_CTYPE_IIO_IFINDEX BIT(3) + +struct icmp_ext_iio_name_subobj { + u8 len; + char name[IFNAMSIZ]; +}; + +enum { + /* RFC 5837 - Incoming IP Interface Role */ + ICMP_ERR_EXT_IIO_IIF, + /* Add new constants above. Used by "icmp_errors_extension_mask" + * sysctl. + */ + ICMP_ERR_EXT_COUNT, +}; + #endif /* _LINUX_ICMP_H */ diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h index 34eb3aecb3f2..0e96c90e56c6 100644 --- a/include/net/netns/ipv4.h +++ b/include/net/netns/ipv4.h @@ -135,6 +135,7 @@ struct netns_ipv4 { u8 sysctl_icmp_echo_ignore_broadcasts; u8 sysctl_icmp_ignore_bogus_error_responses; u8 sysctl_icmp_errors_use_inbound_ifaddr; + u8 sysctl_icmp_errors_extension_mask; int sysctl_icmp_ratelimit; int sysctl_icmp_ratemask; int sysctl_icmp_msgs_per_sec; |