kernel/linux.git/include/uapi/linux/in.h, branch v6.19.11

include: uapi: protocol number and packet structs for AGGFRAG in ESP

2024-12-05T09:01:09+00:00

Add the RFC assigned IP protocol number for AGGFRAG. Add the on-wire basic and congestion-control IP-TFS packet headers. Signed-off-by: Christian Hopps Tested-by: Antony Antony Signed-off-by: Steffen Klassert

net: Correct spelling in headers

2024-08-26T16:37:23+00:00

Correct spelling in Networking headers. As reported by codespell. Signed-off-by: Simon Horman Link: https://patch.msgid.link/20240822-net-spell-v1-12-3a98971ce2d2@kernel.org Signed-off-by: Jakub Kicinski

net/smc: Introduce IPPROTO_SMC

2024-06-17T12:14:09+00:00

This patch allows to create smc socket via AF_INET, similar to the following code, /* create v4 smc sock */ v4 = socket(AF_INET, SOCK_STREAM, IPPROTO_SMC); /* create v6 smc sock */ v6 = socket(AF_INET6, SOCK_STREAM, IPPROTO_SMC); There are several reasons why we believe it is appropriate here: 1. For smc sockets, it actually use IPv4 (AF-INET) or IPv6 (AF-INET6) address. There is no AF_SMC address at all. 2. Create smc socket in the AF_INET(6) path, which allows us to reuse the infrastructure of AF_INET(6) path, such as common ebpf hooks. Otherwise, smc have to implement it again in AF_SMC path. Signed-off-by: D. Wythe Reviewed-by: Wenjia Zhang Reviewed-by: Dust Li Tested-by: Niklas Schnelle Tested-by: Wenjia Zhang Signed-off-by: David S. Miller

ipv{4,6}/raw: fix output xfrm lookup wrt protocol

2023-05-23T13:38:59+00:00

With a raw socket bound to IPPROTO_RAW (ie with hdrincl enabled), the protocol field of the flow structure, build by raw_sendmsg() / rawv6_sendmsg()), is set to IPPROTO_RAW. This breaks the ipsec policy lookup when some policies are defined with a protocol in the selector. For ipv6, the sin6_port field from 'struct sockaddr_in6' could be used to specify the protocol. Just accept all values for IPPROTO_RAW socket. For ipv4, the sin_port field of 'struct sockaddr_in' could not be used without breaking backward compatibility (the value of this field was never checked). Let's add a new kind of control message, so that the userland could specify which protocol is used. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") CC: stable@vger.kernel.org Signed-off-by: Nicolas Dichtel Link: https://lore.kernel.org/r/20230522120820.1319391-1-nicolas.dichtel@6wind.com Signed-off-by: Paolo Abeni

inet: Add IP_LOCAL_PORT_RANGE socket option

2023-01-26T06:45:00+00:00

Users who want to share a single public IP address for outgoing connections between several hosts traditionally reach for SNAT. However, SNAT requires state keeping on the node(s) performing the NAT. A stateless alternative exists, where a single IP address used for egress can be shared between several hosts by partitioning the available ephemeral port range. In such a setup: 1. Each host gets assigned a disjoint range of ephemeral ports. 2. Applications open connections from the host-assigned port range. 3. Return traffic gets routed to the host based on both, the destination IP and the destination port. An application which wants to open an outgoing connection (connect) from a given port range today can choose between two solutions: 1. Manually pick the source port by bind()'ing to it before connect()'ing the socket. This approach has a couple of downsides: a) Search for a free port has to be implemented in the user-space. If the chosen 4-tuple happens to be busy, the application needs to retry from a different local port number. Detecting if 4-tuple is busy can be either easy (TCP) or hard (UDP). In TCP case, the application simply has to check if connect() returned an error (EADDRNOTAVAIL). That is assuming that the local port sharing was enabled (REUSEADDR) by all the sockets. # Assume desired local port range is 60_000-60_511 s = socket(AF_INET, SOCK_STREAM) s.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1) s.bind(("192.0.2.1", 60_000)) s.connect(("1.1.1.1", 53)) # Fails only if 192.0.2.1:60000 -> 1.1.1.1:53 is busy # Application must retry with another local port In case of UDP, the network stack allows binding more than one socket to the same 4-tuple, when local port sharing is enabled (REUSEADDR). Hence detecting the conflict is much harder and involves querying sock_diag and toggling the REUSEADDR flag [1]. b) For TCP, bind()-ing to a port within the ephemeral port range means that no connecting sockets, that is those which leave it to the network stack to find a free local port at connect() time, can use the this port. IOW, the bind hash bucket tb->fastreuse will be 0 or 1, and the port will be skipped during the free port search at connect() time. 2. Isolate the app in a dedicated netns and use the use the per-netns ip_local_port_range sysctl to adjust the ephemeral port range bounds. The per-netns setting affects all sockets, so this approach can be used only if: - there is just one egress IP address, or - the desired egress port range is the same for all egress IP addresses used by the application. For TCP, this approach avoids the downsides of (1). Free port search and 4-tuple conflict detection is done by the network stack: system("sysctl -w net.ipv4.ip_local_port_range='60000 60511'") s = socket(AF_INET, SOCK_STREAM) s.setsockopt(SOL_IP, IP_BIND_ADDRESS_NO_PORT, 1) s.bind(("192.0.2.1", 0)) s.connect(("1.1.1.1", 53)) # Fails if all 4-tuples 192.0.2.1:60000-60511 -> 1.1.1.1:53 are busy For UDP this approach has limited applicability. Setting the IP_BIND_ADDRESS_NO_PORT socket option does not result in local source port being shared with other connected UDP sockets. Hence relying on the network stack to find a free source port, limits the number of outgoing UDP flows from a single IP address down to the number of available ephemeral ports. To put it another way, partitioning the ephemeral port range between hosts using the existing Linux networking API is cumbersome. To address this use case, add a new socket option at the SOL_IP level, named IP_LOCAL_PORT_RANGE. The new option can be used to clamp down the ephemeral port range for each socket individually. The option can be used only to narrow down the per-netns local port range. If the per-socket range lies outside of the per-netns range, the latter takes precedence. UAPI-wise, the low and high range bounds are passed to the kernel as a pair of u16 values in host byte order packed into a u32. This avoids pointer passing. PORT_LO = 40_000 PORT_HI = 40_511 s = socket(AF_INET, SOCK_STREAM) v = struct.pack("I", PORT_HI << 16 | PORT_LO) s.setsockopt(SOL_IP, IP_LOCAL_PORT_RANGE, v) s.bind(("127.0.0.1", 0)) s.getsockname() # Local address between ("127.0.0.1", 40_000) and ("127.0.0.1", 40_511), # if there is a free port. EADDRINUSE otherwise. [1] https://github.com/cloudflare/cloudflare-blog/blob/232b432c1d57/2022-02-connectx/connectx.py#L116 Reviewed-by: Marek Majkowski Reviewed-by: Kuniyuki Iwashima Signed-off-by: Jakub Sitnicki Reviewed-by: Eric Dumazet Signed-off-by: Jakub Kicinski

net/ipv4: Fix linux/in.h header dependencies

2022-11-03T12:44:46+00:00

__DECLARE_FLEX_ARRAY is defined in include/uapi/linux/stddef.h but doesn't seem to be explicitly included from include/uapi/linux/in.h, which breaks BPF selftests builds (once we sync linux/stddef.h into tools/include directory in the next patch). Fix this by explicitly including linux/stddef.h. Given this affects BPF CI and bpf tree, targeting this for bpf tree. Fixes: 5854a09b4957 ("net/ipv4: Use __DECLARE_FLEX_ARRAY() helper") Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Cc: Gustavo A. R. Silva Cc: Jakub Kicinski Link: https://lore.kernel.org/bpf/20221102182517.2675301-1-andrii@kernel.org

uapi: move IPPROTO_L2TP to in.h

2022-09-20T07:13:38+00:00

IPPROTO_L2TP is currently defined in l2tp.h, but most of ip protocols are defined in in.h file. Move it there in order to keep code clean. Acked-by: Guillaume Nault Signed-off-by: Wojciech Drewek Signed-off-by: Tony Nguyen Signed-off-by: Paolo Abeni

net/ipv4: Use __DECLARE_FLEX_ARRAY() helper

2022-09-03T08:51:10+00:00

We now have a cleaner way to keep compatibility with user-space (a.k.a. not breaking it) when we need to keep in place a one-element array (for its use in user-space) together with a flexible-array member (for its use in kernel-space) without making it hard to read at the source level. This is through the use of the new __DECLARE_FLEX_ARRAY() helper macro. The size and memory layout of the structure is preserved after the changes. See below. Before changes: $ pahole -C ip_msfilter net/ipv4/igmp.o struct ip_msfilter { union { struct { __be32 imsf_multiaddr_aux; /* 0 4 */ __be32 imsf_interface_aux; /* 4 4 */ __u32 imsf_fmode_aux; /* 8 4 */ __u32 imsf_numsrc_aux; /* 12 4 */ __be32 imsf_slist[1]; /* 16 4 */ }; /* 0 20 */ struct { __be32 imsf_multiaddr; /* 0 4 */ __be32 imsf_interface; /* 4 4 */ __u32 imsf_fmode; /* 8 4 */ __u32 imsf_numsrc; /* 12 4 */ __be32 imsf_slist_flex[0]; /* 16 0 */ }; /* 0 16 */ }; /* 0 20 */ /* size: 20, cachelines: 1, members: 1 */ /* last cacheline: 20 bytes */ }; After changes: $ pahole -C ip_msfilter net/ipv4/igmp.o struct ip_msfilter { __be32 imsf_multiaddr; /* 0 4 */ __be32 imsf_interface; /* 4 4 */ __u32 imsf_fmode; /* 8 4 */ __u32 imsf_numsrc; /* 12 4 */ union { __be32 imsf_slist[1]; /* 16 4 */ struct { struct { } __empty_imsf_slist_flex; /* 16 0 */ __be32 imsf_slist_flex[0]; /* 16 0 */ }; /* 16 0 */ }; /* 16 4 */ /* size: 20, cachelines: 1, members: 5 */ /* last cacheline: 20 bytes */ }; In the past, we had to duplicate the whole original structure within a union, and update the names of all the members. Now, we just need to declare the flexible-array member to be used in kernel-space through the __DECLARE_FLEX_ARRAY() helper together with the one-element array, within a union. This makes the source code more clean and easier to read. Link: https://github.com/KSPP/linux/issues/193 Signed-off-by: Gustavo A. R. Silva Reviewed-by: Kees Cook Signed-off-by: David S. Miller

net/ipv4/ipv6: Replace one-element arraya with flexible-array members

2021-08-05T10:46:42+00:00

There is a regular need in the kernel to provide a way to declare having a dynamically sized set of trailing elements in a structure. Kernel code should always use “flexible array members”[1] for these cases. The older style of one-element or zero-length arrays should no longer be used[2]. Use an anonymous union with a couple of anonymous structs in order to keep userspace unchanged and refactor the related code accordingly: $ pahole -C group_filter net/ipv4/ip_sockglue.o struct group_filter { union { struct { __u32 gf_interface_aux; /* 0 4 */ /* XXX 4 bytes hole, try to pack */ struct __kernel_sockaddr_storage gf_group_aux; /* 8 128 */ /* --- cacheline 2 boundary (128 bytes) was 8 bytes ago --- */ __u32 gf_fmode_aux; /* 136 4 */ __u32 gf_numsrc_aux; /* 140 4 */ struct __kernel_sockaddr_storage gf_slist[1]; /* 144 128 */ }; /* 0 272 */ struct { __u32 gf_interface; /* 0 4 */ /* XXX 4 bytes hole, try to pack */ struct __kernel_sockaddr_storage gf_group; /* 8 128 */ /* --- cacheline 2 boundary (128 bytes) was 8 bytes ago --- */ __u32 gf_fmode; /* 136 4 */ __u32 gf_numsrc; /* 140 4 */ struct __kernel_sockaddr_storage gf_slist_flex[0]; /* 144 0 */ }; /* 0 144 */ }; /* 0 272 */ /* size: 272, cachelines: 5, members: 1 */ /* last cacheline: 16 bytes */ }; $ pahole -C compat_group_filter net/ipv4/ip_sockglue.o struct compat_group_filter { union { struct { __u32 gf_interface_aux; /* 0 4 */ struct __kernel_sockaddr_storage gf_group_aux __attribute__((__aligned__(4))); /* 4 128 */ /* --- cacheline 2 boundary (128 bytes) was 4 bytes ago --- */ __u32 gf_fmode_aux; /* 132 4 */ __u32 gf_numsrc_aux; /* 136 4 */ struct __kernel_sockaddr_storage gf_slist[1] __attribute__((__aligned__(4))); /* 140 128 */ } __attribute__((__packed__)) __attribute__((__aligned__(4))); /* 0 268 */ struct { __u32 gf_interface; /* 0 4 */ struct __kernel_sockaddr_storage gf_group __attribute__((__aligned__(4))); /* 4 128 */ /* --- cacheline 2 boundary (128 bytes) was 4 bytes ago --- */ __u32 gf_fmode; /* 132 4 */ __u32 gf_numsrc; /* 136 4 */ struct __kernel_sockaddr_storage gf_slist_flex[0] __attribute__((__aligned__(4))); /* 140 0 */ } __attribute__((__packed__)) __attribute__((__aligned__(4))); /* 0 140 */ } __attribute__((__aligned__(1))); /* 0 268 */ /* size: 268, cachelines: 5, members: 1 */ /* forced alignments: 1 */ /* last cacheline: 12 bytes */ } __attribute__((__packed__)); This helps with the ongoing efforts to globally enable -Warray-bounds and get us closer to being able to tighten the FORTIFY_SOURCE routines on memcpy(). [1] https://en.wikipedia.org/wiki/Flexible_array_member [2] https://www.kernel.org/doc/html/v5.10/process/deprecated.html#zero-length-and-one-element-arrays Link: https://github.com/KSPP/linux/issues/79 Link: https://github.com/KSPP/linux/issues/109 Signed-off-by: Gustavo A. R. Silva Signed-off-by: David S. Miller

net/ipv4: Replace one-element array with flexible-array member

2021-08-02T14:17:28+00:00