176 lines
5.3 KiB
Diff
176 lines
5.3 KiB
Diff
From c724812d9561021fb6a80c817d411d9ba2de5dbd Mon Sep 17 00:00:00 2001
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From: Phil Sutter <psutter@redhat.com>
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Date: Tue, 13 Jul 2021 13:54:12 +0200
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Subject: [PATCH] scanner: introduce start condition stack
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Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1979334
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Upstream Status: nftables commit 5896772fe3c5f
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commit 5896772fe3c5f01696188ea04957a825ee601b12
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Author: Florian Westphal <fw@strlen.de>
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Date: Mon Mar 8 18:18:33 2021 +0100
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scanner: introduce start condition stack
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Add a small initial chunk of flex start conditionals.
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This starts with two low-hanging fruits, numgen and j/symhash.
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NUMGEN and HASH start conditions are entered from flex when
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the corresponding expression token is encountered.
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Flex returns to the INIT condition when the bison parser
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has seen a complete numgen/hash statement.
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This intentionally uses a stack rather than BEGIN()
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to eventually support nested states.
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The scanner_pop_start_cond() function argument is not used yet, but
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will need to be used later to deal with nesting.
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Signed-off-by: Florian Westphal <fw@strlen.de>
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---
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include/parser.h | 8 ++++++++
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src/parser_bison.y | 11 +++++++----
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src/scanner.l | 36 +++++++++++++++++++++++++++++-------
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3 files changed, 44 insertions(+), 11 deletions(-)
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diff --git a/include/parser.h b/include/parser.h
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index 949284d..1d293f5 100644
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--- a/include/parser.h
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+++ b/include/parser.h
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@@ -28,6 +28,12 @@ struct parser_state {
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struct list_head *cmds;
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};
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+enum startcond_type {
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+ PARSER_SC_BEGIN,
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+ PARSER_SC_EXPR_HASH,
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+ PARSER_SC_EXPR_NUMGEN,
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+};
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+
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struct mnl_socket;
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extern void parser_init(struct nft_ctx *nft, struct parser_state *state,
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@@ -47,4 +53,6 @@ extern void scanner_push_buffer(void *scanner,
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const struct input_descriptor *indesc,
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const char *buffer);
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+extern void scanner_pop_start_cond(void *scanner, enum startcond_type sc);
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+
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#endif /* NFTABLES_PARSER_H */
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diff --git a/src/parser_bison.y b/src/parser_bison.y
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index 5aedc55..9a9447f 100644
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--- a/src/parser_bison.y
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+++ b/src/parser_bison.y
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@@ -840,6 +840,9 @@ opt_newline : NEWLINE
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| /* empty */
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;
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+close_scope_hash : { scanner_pop_start_cond(nft->scanner, PARSER_SC_EXPR_HASH); };
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+close_scope_numgen : { scanner_pop_start_cond(nft->scanner, PARSER_SC_EXPR_NUMGEN); };
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+
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common_block : INCLUDE QUOTED_STRING stmt_separator
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{
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if (scanner_include_file(nft, scanner, $2, &@$) < 0) {
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@@ -4249,7 +4252,7 @@ numgen_type : INC { $$ = NFT_NG_INCREMENTAL; }
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| RANDOM { $$ = NFT_NG_RANDOM; }
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;
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-numgen_expr : NUMGEN numgen_type MOD NUM offset_opt
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+numgen_expr : NUMGEN numgen_type MOD NUM offset_opt close_scope_numgen
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{
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$$ = numgen_expr_alloc(&@$, $2, $4, $5);
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}
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@@ -4306,17 +4309,17 @@ xfrm_expr : IPSEC xfrm_dir xfrm_spnum xfrm_state_key
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}
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;
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-hash_expr : JHASH expr MOD NUM SEED NUM offset_opt
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+hash_expr : JHASH expr MOD NUM SEED NUM offset_opt close_scope_hash
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{
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$$ = hash_expr_alloc(&@$, $4, true, $6, $7, NFT_HASH_JENKINS);
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$$->hash.expr = $2;
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}
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- | JHASH expr MOD NUM offset_opt
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+ | JHASH expr MOD NUM offset_opt close_scope_hash
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{
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$$ = hash_expr_alloc(&@$, $4, false, 0, $5, NFT_HASH_JENKINS);
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$$->hash.expr = $2;
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}
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- | SYMHASH MOD NUM offset_opt
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+ | SYMHASH MOD NUM offset_opt close_scope_hash
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{
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$$ = hash_expr_alloc(&@$, $3, false, 0, $4, NFT_HASH_SYM);
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}
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diff --git a/src/scanner.l b/src/scanner.l
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index 20b1b2d..68fe988 100644
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--- a/src/scanner.l
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+++ b/src/scanner.l
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@@ -98,6 +98,8 @@ static void reset_pos(struct parser_state *state, struct location *loc)
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state->indesc->column = 1;
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}
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+static void scanner_push_start_cond(void *scanner, enum startcond_type type);
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+
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#define YY_USER_ACTION { \
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update_pos(yyget_extra(yyscanner), yylloc, yyleng); \
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update_offset(yyget_extra(yyscanner), yylloc, yyleng); \
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@@ -193,6 +195,9 @@ addrstring ({macaddr}|{ip4addr}|{ip6addr})
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%option yylineno
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%option nodefault
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%option warn
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+%option stack
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+%s SCANSTATE_EXPR_HASH
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+%s SCANSTATE_EXPR_NUMGEN
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%%
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@@ -548,15 +553,21 @@ addrstring ({macaddr}|{ip4addr}|{ip6addr})
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"state" { return STATE; }
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"status" { return STATUS; }
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-"numgen" { return NUMGEN; }
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-"inc" { return INC; }
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-"mod" { return MOD; }
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-"offset" { return OFFSET; }
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+"numgen" { scanner_push_start_cond(yyscanner, SCANSTATE_EXPR_NUMGEN); return NUMGEN; }
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+<SCANSTATE_EXPR_NUMGEN>{
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+ "inc" { return INC; }
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+}
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-"jhash" { return JHASH; }
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-"symhash" { return SYMHASH; }
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-"seed" { return SEED; }
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+"jhash" { scanner_push_start_cond(yyscanner, SCANSTATE_EXPR_HASH); return JHASH; }
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+"symhash" { scanner_push_start_cond(yyscanner, SCANSTATE_EXPR_HASH); return SYMHASH; }
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+<SCANSTATE_EXPR_HASH>{
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+ "seed" { return SEED; }
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+}
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+<SCANSTATE_EXPR_HASH,SCANSTATE_EXPR_NUMGEN>{
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+ "mod" { return MOD; }
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+ "offset" { return OFFSET; }
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+}
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"dup" { return DUP; }
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"fwd" { return FWD; }
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@@ -949,3 +960,14 @@ void scanner_destroy(struct nft_ctx *nft)
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input_descriptor_list_destroy(state);
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yylex_destroy(nft->scanner);
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}
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+
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+static void scanner_push_start_cond(void *scanner, enum startcond_type type)
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+{
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+ yy_push_state((int)type, scanner);
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+}
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+
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+void scanner_pop_start_cond(void *scanner, enum startcond_type t)
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+{
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+ yy_pop_state(scanner);
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+ (void)yy_top_state(scanner); /* suppress gcc warning wrt. unused function */
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+}
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--
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2.31.1
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