[mcast] merge main + handle stage changes associated + cleanup

The sidecar pipeline lands at 16 ingress stages without multicast and 19 with multicast,
all without sacrificing unicast LPM capacity in either build.

Includes:

* Merges origin/main, picking up the RFD 619 dpd-api refactor (#259).
* v6 unicast TTL=1 handling via per-prefix skip_ttl bit + inline check
 (saves a stage vs the v4-style compound TTL key). Service-port routes skip the
 TTL exception so userspace still receives the packet. This helped after the
 table-sizing changes on main (and making MCAST align).
* Multicast tables are now sized per-workload (separate constants per table) rather
  than via a single global ceiling.
* Lots of misc cleanup.

Author: zeeshanlakhani

.github/buildomat/common.sh

@@ -1,11 +1,17 @@
 #!/bin/bash
 
-# The tofino2 has 20 stages. The base sidecar.p4 needs 15 stages, and with
-# multicast enabled it needs 18. Specifying the number of stages isn't
+# The tofino2 has 20 stages. The base sidecar.p4 builds at 16 stages, and,
+# with multicast enabled, at 19. Specifying the number of stages isn't
 # strictly necessary, but it allows us to track when we exceed the current
 # ceiling. The underlying intention is to grow deliberately and thoughtfully,
 # given the limited space on the ASIC.
-TOFINO_STAGES=15
+#
+# Note: p4c does multiple placement rounds. table_summary.log reports each
+# round. The first (unconstrained) is informational, and the final (at the
+# bottom of the log) is what the binary actually uses. If
+# --num-stages-override cannot be satisfied, the assembler errors out and
+# no binary is produced.
+TOFINO_STAGES=16
 
 # These describe which version of the SDE to download and where to find it
 SDE_COMMIT=2a6b33211c9675996dcb99fe939045506667ae94

.github/buildomat/packet-test-common.sh

@@ -19,9 +19,9 @@ if [ x$MULTICAST == x ]; then
 fi
 
 if [ x$MULTICAST == x ]; then
-        TOFINO_STAGES=15
+        TOFINO_STAGES=16
     else
-        TOFINO_STAGES=18
+        TOFINO_STAGES=19
 fi
 
 function cleanup {

Cargo.lock

@@ -9,6 +9,7 @@ members = [
 	"dpd-api",
 	"dpd-client",
 	"dpd-types",
+	"dpd-types/versions",
 	"dropshot-apis",
 	"packet",
 	"pcap",
@@ -35,6 +36,7 @@ asic = { path = "asic" }
 dpd-api = { path = "dpd-api" }
 dpd-client = { path = "dpd-client" }
 dpd-types = { path = "dpd-types" }
+dpd-types-versions = { path = "dpd-types/versions" }
 common = { path = "common" }
 packet = { path = "packet" }
 pcap = { path = "pcap" }

Cargo.toml

@@ -32,6 +32,11 @@ To build the p4 program:
 $ cargo xtask codegen [ -n <p4 program name> ] [--sde <sde directory> ]
 ```
 
+*Note*: The final stage count for the binary is reported in
+`target/proto/opt/oxide/dendrite/sidecar/pipe/logs/table_summary.log`.
+If the requested stage allotment cannot be met, the assembler errors
+out and no binary is produced.
+
 The Tofino model is not yet available for `illumos`/`helios`.  To run the
 compiled p4 program on the Tofino model on a Linux system:
 

README.md

@@ -23,7 +23,7 @@ doctest = false
 [dependencies]
 aal.workspace = true
 common.workspace = true
-dpd-api.workspace = true
+dpd-types.workspace = true
 
 propolis = { workspace = true, optional = true , features = ["falcon"] }
 tofino = { workspace = true, optional = true }

asic/Cargo.toml

@@ -16,7 +16,7 @@ use crate::tofino_asic::genpd::*;
 use crate::tofino_asic::ports;
 use crate::tofino_asic::{CheckError, Handle};
 use aal::{AsicError, AsicResult, PortHdl};
-use dpd_api::{
+use dpd_types::serdes::{
     AnLtStatus, AnStatus, DfeAdaptationState, EncSpeed, LaneEncoding, LaneMap,
     LaneStatus, LpPages, LtStatus, RxSigInfo, SerdesEye,
 };

asic/src/tofino_asic/serdes.rs

@@ -6,6 +6,7 @@
 
 use std::collections::HashMap;
 use std::ffi::OsStr;
+use std::fs;
 use std::path::PathBuf;
 
 use serde::Deserialize;
@@ -348,6 +349,10 @@ fn infer_p4_dir() -> AsicResult<String> {
     let mut exe_path = std::env::current_exe().map_err(|e| {
         AsicError::P4Missing(format!("looking up dpd path: {e:?}"))
     })?;
+    // Canonicalize the path in case we're using a symlinked exe.
+    exe_path = fs::canonicalize(exe_path).map_err(|e| {
+        AsicError::P4Missing(format!("canonicalizing dpd path: {e:?}"))
+    })?;
 
     // Pop off the trailing "dpd":
     exe_path = expect_name(exe_path, "dpd")?;

asic/src/tofino_common/mod.rs

@@ -6,10 +6,7 @@ edition = "2024"
 [dependencies]
 common.workspace = true
 dpd-types.workspace = true
+dpd-types-versions.workspace = true
 dropshot.workspace = true
 dropshot-api-manager-types.workspace = true
-oxnet.workspace = true
-schemars.workspace = true
-serde.workspace = true
 transceiver-controller.workspace = true
-uuid.workspace = true