On Thu, Aug 03, 2023 at 03:30:39PM +0800, Geliang Tang wrote:
Add a hook named update_socket_protocol in __sys_socket(), for bpf progs to attach to and update socket protocol. One user case is to force legacy TCP apps to create and use MPTCP sockets instead of TCP ones.
Define a mod_ret set named bpf_mptcp_fmodret_ids, add the hook update_socket_protocol into this set, and register it in bpf_mptcp_kfunc_init().
Signed-off-by: Geliang Tang geliang.tang@suse.com
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diff --git a/net/socket.c b/net/socket.c index 2b0e54b2405c..586a437d7a5e 100644 --- a/net/socket.c +++ b/net/socket.c @@ -1644,11 +1644,36 @@ struct file *__sys_socket_file(int family, int type, int protocol) return sock_alloc_file(sock, flags, NULL); } +/**
Hi Geliang Tang,
nit: The format of the text below is not in kernel doc format, so it is probably better if the comment begins with '/*' rather than '/**'.
- A hook for bpf progs to attach to and update socket protocol.
- A static noinline declaration here could cause the compiler to
- optimize away the function. A global noinline declaration will
- keep the definition, but may optimize away the callsite.
- Therefore, __weak is needed to ensure that the call is still
- emitted, by telling the compiler that we don't know what the
- function might eventually be.
- __diag_* below are needed to dismiss the missing prototype warning.
- */
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