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charset="UTF-8" User-Agent: Evolution 3.52.3-0ubuntu1 Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Tue, 2024-09-03 at 11:11 +0200, Matthieu Baerts wrote: > Hi Geliang, > > Thank you for the new version. > > On 03/09/2024 10:04, Geliang Tang wrote: > > From: Geliang Tang > > > > This patch adds a "cgroup/getsockopt" way to inspect the subflows > > of a > > mptcp socket. > > > > mptcp_for_each_stubflow() and other helpers related to list_dentry > > are > > added into progs/mptcp_bpf.h. > > > > Add an extra "cgroup/getsockopt" prog to walk the msk->conn_list > > and use > > bpf_core_cast to cast a pointer to tcp_sock for readonly. It will > > allow > > to inspect all the fields in a tcp_sock. > > (...) > > > diff --git a/tools/testing/selftests/bpf/progs/mptcp_subflow.c > > b/tools/testing/selftests/bpf/progs/mptcp_subflow.c > > index 2e28f4a215b5..1053a795eb43 100644 > > --- a/tools/testing/selftests/bpf/progs/mptcp_subflow.c > > +++ b/tools/testing/selftests/bpf/progs/mptcp_subflow.c > > @@ -4,6 +4,7 @@ > >   > >  /* vmlinux.h, bpf_helpers.h and other 'define' */ > >  #include "bpf_tracing_net.h" > > +#include "mptcp_bpf.h" > >   > >  char _license[] SEC("license") = "GPL"; > >   > > @@ -57,3 +58,92 @@ int mptcp_subflow(struct bpf_sock_ops *skops) > >   > >   return 1; > >  } > > + > > +static int _check_getsockopt_subflow_mark(struct bpf_sock *sk) > > +{ > > + struct mptcp_subflow_context *subflow; > > + struct mptcp_sock *msk; > > + int i = 0; > > + > > + if (sk->protocol != IPPROTO_MPTCP) { > > + bpf_printk("MPTCP Subflow: unexpected protocol > > %u", sk->protocol); > > + return -1; > > + } > > Out of curiosity, why did you move this code here and in > _check_getsockopt_subflow_cc()? > > I'm just surprised because recently, you tried to reduce the amount > of > duplicated code :) > > Or is it because this program is used in other tests, where it should > not be? Do you need to add a restriction per PID, like you did in > mptcpify.c? I don't know, I'll add "per PID" in next version. > > (...) > > > +SEC("cgroup/getsockopt") > > +int _getsockopt_subflow(struct bpf_sockopt *ctx) > > +{ > > + struct bpf_sock *sk = ctx->sk; > > + > > + if (!sk) { > > + bpf_printk("MPTCP Subflow: unexpected socket, sk > > is NULL"); > > + ctx->retval = -1; > > + return 1; > > + } > > + > > + if (ctx->level == SOL_SOCKET && ctx->optname == SO_MARK) > > + ctx->retval = _check_getsockopt_subflow_mark(sk); > > + else if (ctx->level == SOL_TCP && ctx->optname == > > TCP_CONGESTION) > > + ctx->retval = _check_getsockopt_subflow_cc(sk); > > As I mentioned in my previous reply: can ctx->retval be < 0 here, > before > calling _check_getsockopt_subflow_XXX()? > If yes or not sure, maybe safer to do: > >   err = _check_getsockopt_subflow_XXX() >   (...) > >   if (err) >       ctx->retval = -1; else ctx->retval = 0; Otherwise: 86: (63) *(u32 *)(r6 +0) = r1 dereference of modified ctx ptr R6 off=36 disallowed processed 169 insns (limit 1000000) max_states_per_insn 2 total_states 15 peak_states 15 mark_read 4 -- END PROG LOAD LOG -- > > > + > > + return 1; > > +} > > Cheers, > Matt