proxy: add 'valcrc' inspector step

Returns the crc32c (iSCSI crc32?) of the value (minus \r\n) of a
request.

Also fixes some tests that I left commented somehow :(

proto_proxy.c

@@ -354,6 +354,7 @@ void *proxy_init(bool use_uring, bool proxy_memprofile) {
     proxy_ctx_t *ctx = calloc(1, sizeof(proxy_ctx_t));
     ctx->use_uring = use_uring;
     ctx->memprofile = proxy_memprofile;
+    crc32c_init();
 
     pthread_mutex_init(&ctx->config_lock, NULL);
     pthread_cond_init(&ctx->config_cond, NULL);

proxy.h

@@ -32,6 +32,8 @@
 #define XXH_INLINE_ALL // modifier for xxh3's include below
 #include "xxhash.h"
 
+#include "crc32c.h"
+
 #ifdef PROXY_DEBUG
 #define P_DEBUG(...) \
     do { \

proxy_inspector.c

@@ -16,6 +16,7 @@ enum mcp_ins_steptype {
     mcp_ins_step_flagtoken,
     mcp_ins_step_flagint,
     mcp_ins_step_flagis,
+    mcp_ins_step_valcrc,
     mcp_ins_step_final, // not used.
 };
 
@@ -473,6 +474,30 @@ static int mcp_inspector_flagis_r(lua_State *L, struct mcp_inspector *ins, struc
     return 2;
 }
 
+static int mcp_inspector_valcrc_c(lua_State *L, int tidx) {
+    return 0;
+}
+
+static int mcp_inspector_valcrc_i(lua_State *L, int tidx, int sc, struct mcp_inspector *ins) {
+    return 0;
+}
+
+static int mcp_inspector_valcrc_r(lua_State *L, struct mcp_inspector *ins, struct mcp_ins_step *s, void *arg) {
+    if (ins->type == INS_REQ) {
+        mcp_request_t *rq = arg;
+        if (rq->pr.vlen > 2 && rq->pr.vbuf) {
+            // don't skip the "\r\n"
+            uint32_t crc = crc32c(0, rq->pr.vbuf, rq->pr.vlen-2);
+            lua_pushinteger(L, crc);
+        } else {
+            lua_pushnil(L);
+        }
+    } else {
+        lua_pushnil(L);
+    }
+    return 1;
+}
+
 // END STEPS
 
 typedef int (*mcp_ins_c)(lua_State *L, int tidx);
@@ -497,6 +522,7 @@ static const struct mcp_ins_entry mcp_ins_entries[] = {
     [mcp_ins_step_flagtoken] = {"flagtoken", mcp_inspector_flag_c_g, mcp_inspector_flag_i_g, mcp_inspector_flagtoken_r, INS_REQ|INS_RES, 2},
     [mcp_ins_step_flagint] = {"flagint", mcp_inspector_flag_c_g, mcp_inspector_flag_i_g, mcp_inspector_flagint_r, INS_REQ|INS_RES, 2},
     [mcp_ins_step_flagis] = {"flagis", mcp_inspector_flagstr_c, mcp_inspector_flagstr_i, mcp_inspector_flagis_r, INS_REQ|INS_RES, 2},
+    [mcp_ins_step_valcrc] = {"valcrc", mcp_inspector_valcrc_c, mcp_inspector_valcrc_i, mcp_inspector_valcrc_r, INS_REQ, 1},
 };
 
 // call with type string on top
@@ -639,6 +665,7 @@ int mcplib_inspector_gc(lua_State *L) {
             case mcp_ins_step_flagtoken:
             case mcp_ins_step_flagint:
             case mcp_ins_step_flagis:
+            case mcp_ins_step_valcrc:
             case mcp_ins_step_none:
             case mcp_ins_step_final:
                 break;

t/proxyins.lua

@@ -146,11 +146,41 @@ function mcp_config_routes(p)
         end
     })
 
+    local msvalcrc_ins = mcp.req_inspector_new(
+        { t = "valcrc" }
+    )
+
+    local msfg = mcp.funcgen_new()
+    msfg:ready({
+        n = "msfg", f = function(rctx)
+            return function(r)
+                -- only one test right now.
+                local crc = msvalcrc_ins(r)
+                return string.format("SERVER_ERROR crc[%q]\r\n", crc)
+            end
+        end
+    })
+
+    local msint = mcp.funcgen_new()
+    msint:ready({
+        n = "msint", f = function(rctx)
+            return function(r)
+                return mcp.internal(r)
+            end
+        end
+    })
+
     local mgr = mcp.router_new({ map = {
         sepkey = mgsepkey,
         reshasf = mgreshasf,
         reqkey = mgreqkey,
         intres = mgintres,
     }})
+
+    local msr = mcp.router_new({ map = {
+        all = msfg,
+        intres = msint,
+    }})
     mcp.attach(mcp.CMD_MG, mgr)
+    mcp.attach(mcp.CMD_MS, msr)
 end

t/proxyins.t

@@ -30,9 +30,18 @@ print $w "watch proxyevents\r\n";
 is(<$w>, "OK\r\n");
 
 {
+    test_msreq();
     test_mgintres();
-    #test_mgreq();
-    #test_mgres();
+    test_mgreq();
+    test_mgres();
+}
+
+sub test_msreq {
+    note 'testing ms req';
+    subtest 'valcrc' => sub {
+        $t->c_send("ms all/valcrc 5\r\nhello\r\n");
+        $t->c_recv("SERVER_ERROR crc[2591144780]\r\n");
+    }
 }
 
 sub test_mgintres {