| Message ID | 20210804181516.11921-1-yepeilin.cs@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | [iproute2-next,v3] tc/skbmod: Introduce SKBMOD_F_ECN option | expand |
On 8/4/21 12:15 PM, Peilin Ye wrote: > From: Peilin Ye <peilin.ye@bytedance.com> > > Recently we added SKBMOD_F_ECN option support to the kernel; support it in > the tc-skbmod(8) front end, and update its man page accordingly. > > The 2 least significant bits of the Traffic Class field in IPv4 and IPv6 > headers are used to represent different ECN states [1]: > > 0b00: "Non ECN-Capable Transport", Non-ECT > 0b10: "ECN Capable Transport", ECT(0) > 0b01: "ECN Capable Transport", ECT(1) > 0b11: "Congestion Encountered", CE > > This new option, "ecn", marks ECT(0) and ECT(1) IPv{4,6} packets as CE, > which is useful for ECN-based rate limiting. For example: > > $ tc filter add dev eth0 parent 1: protocol ip prio 10 \ > u32 match ip protocol 1 0xff flowid 1:2 \ > action skbmod \ > ecn > > The updated tc-skbmod SYNOPSIS looks like the following: > > tc ... action skbmod { set SETTABLE | swap SWAPPABLE | ecn } ... > > Only one of "set", "swap" or "ecn" shall be used in a single tc-skbmod > command. Trying to use more than one of them at a time is considered > undefined behavior; pipe multiple tc-skbmod commands together instead. > "set" and "swap" only affect Ethernet packets, while "ecn" only affects > IP packets. > > Depends on kernel patch "net/sched: act_skbmod: Add SKBMOD_F_ECN option > support", as well as iproute2 patch "tc/skbmod: Remove misinformation > about the swap action". > > [1] https://en.wikipedia.org/wiki/Explicit_Congestion_Notification > > Reviewed-by: Cong Wang <cong.wang@bytedance.com> > Signed-off-by: Peilin Ye <peilin.ye@bytedance.com> > --- > Hi David, > >> I just merged main into next. Please fix up this patch and re-send. In >> the future, just ask for a merge in cases like this. > > Ah, I see; thanks! > Peilin Ye > > Change since v2: > - re-rebased on iproute2-next (David) > > man/man8/tc-skbmod.8 | 38 +++++++++++++++++++++++++++++--------- > tc/m_skbmod.c | 8 +++++++- > 2 files changed, 36 insertions(+), 10 deletions(-) > applied to iproute2-next.
Hello: This patch was applied to iproute2/iproute2-next.git (refs/heads/main): On Wed, 4 Aug 2021 11:15:16 -0700 you wrote: > From: Peilin Ye <peilin.ye@bytedance.com> > > Recently we added SKBMOD_F_ECN option support to the kernel; support it in > the tc-skbmod(8) front end, and update its man page accordingly. > > The 2 least significant bits of the Traffic Class field in IPv4 and IPv6 > headers are used to represent different ECN states [1]: > > [...] Here is the summary with links: - [iproute2-next,v3] tc/skbmod: Introduce SKBMOD_F_ECN option https://git.kernel.org/pub/scm/network/iproute2/iproute2-next.git/commit/?id=e78411948dc7 You are awesome, thank you! -- Deet-doot-dot, I am a bot. https://korg.docs.kernel.org/patchwork/pwbot.html
diff --git a/man/man8/tc-skbmod.8 b/man/man8/tc-skbmod.8 index 76512311b17d..52eaf989e80b 100644 --- a/man/man8/tc-skbmod.8 +++ b/man/man8/tc-skbmod.8 @@ -8,7 +8,8 @@ skbmod - user-friendly packet editor action .BR tc " ... " "action skbmod " "{ " "set " .IR SETTABLE " | " .BI swap " SWAPPABLE" -.RI " } [ " CONTROL " ] [ " +.RB " | " ecn +.RI "} [ " CONTROL " ] [ " .BI index " INDEX " ] @@ -37,6 +38,12 @@ action. Instead of having to manually edit 8-, 16-, or 32-bit chunks of an ethernet header, .B skbmod allows complete substitution of supported elements. +Action must be one of +.BR set ", " swap " and " ecn "." +.BR set " and " swap +only affect Ethernet packets, while +.B ecn +only affects IP packets. .SH OPTIONS .TP .BI dmac " DMAC" @@ -51,6 +58,10 @@ Change the ethertype to the specified value. .BI mac Used to swap mac addresses. .TP +.B ecn +Used to mark ECN Capable Transport (ECT) IP packets as Congestion Encountered (CE). +Does not affect Non ECN-Capable Transport (Non-ECT) packets. +.TP .I CONTROL The following keywords allow to control how the tree of qdisc, classes, filters and actions is further traversed after this action. @@ -115,7 +126,7 @@ tc filter add dev eth5 parent 1: protocol ip prio 10 \\ .EE .RE -Finally, swap the destination and source mac addresses in the header: +To swap the destination and source mac addresses in the Ethernet header: .RS .EX @@ -126,13 +137,22 @@ tc filter add dev eth3 parent 1: protocol ip prio 10 \\ .EE .RE -However, trying to -.B set -and -.B swap -in a single -.B skbmod -command will cause undefined behavior. +Finally, to mark the CE codepoint in the IP header for ECN Capable Transport (ECT) packets: + +.RS +.EX +tc filter add dev eth0 parent 1: protocol ip prio 10 \\ + u32 match ip protocol 1 0xff flowid 1:2 \\ + action skbmod \\ + ecn +.EE +.RE + +Only one of +.BR set ", " swap " and " ecn +shall be used in a single command. +Trying to use more than one of them in a single command is considered undefined behavior; pipe +multiple commands together instead. .SH SEE ALSO .BR tc (8), diff --git a/tc/m_skbmod.c b/tc/m_skbmod.c index 3fe30651a7d8..8d8bac5bc481 100644 --- a/tc/m_skbmod.c +++ b/tc/m_skbmod.c @@ -28,7 +28,7 @@ static void skbmod_explain(void) { fprintf(stderr, - "Usage:... skbmod { set <SETTABLE> | swap <SWAPPABLE> } [CONTROL] [index INDEX]\n" + "Usage:... skbmod { set <SETTABLE> | swap <SWAPPABLE> | ecn } [CONTROL] [index INDEX]\n" "where SETTABLE is: [dmac DMAC] [smac SMAC] [etype ETYPE]\n" "where SWAPPABLE is: \"mac\" to swap mac addresses\n" "\tDMAC := 6 byte Destination MAC address\n" @@ -111,6 +111,9 @@ static int parse_skbmod(struct action_util *a, int *argc_p, char ***argv_p, p.flags |= SKBMOD_F_SMAC; fprintf(stderr, "src MAC address <%s>\n", saddr); ok += 1; + } else if (matches(*argv, "ecn") == 0) { + p.flags |= SKBMOD_F_ECN; + ok += 1; } else if (matches(*argv, "help") == 0) { skbmod_usage(); } else { @@ -211,6 +214,9 @@ static int print_skbmod(struct action_util *au, FILE *f, struct rtattr *arg) if (p->flags & SKBMOD_F_SWAPMAC) fprintf(f, "swap mac "); + if (p->flags & SKBMOD_F_ECN) + fprintf(f, "ecn "); + fprintf(f, "\n\t index %u ref %d bind %d", p->index, p->refcnt, p->bindcnt); if (show_stats) {