tcpopt: split tcpopt_hdr_fields into per-option enum

Currently we're limited to ten template fields in exthdr_desc struct.
Using a single enum for all tpc option fields thus won't work
indefinitely (TCPOPTHDR_FIELD_TSECR is 9) when new option templates get
added.

Fortunately we can just use one enum per tcp option to avoid this.
As a side effect this also allows to simplify the sack offset
calculations.  Rather than computing that on-the-fly, just add extra
fields to the SACK template.

expr->exthdr.offset now holds the 'raw' value, filled in from the option
template. This would ease implementation of 'raw option matching'
using offset and length to load from the option.

Signed-off-by: Florian Westphal <fw@strlen.de>

diff --git a/include/tcpopt.h b/include/tcpopt.h
index 7f3fbb8b0c7d1400609b6bbb3474ad74d286baba..667c8a7725d8992b118a9d223cfa57479c81c99f 100644 (file)
--- a/include/tcpopt.h
+++ b/include/tcpopt.h
@@ -33,16 +33,42 @@ enum tcpopt_kind {
        TCPOPT_KIND_SACK3 = 258,
 };
 
-enum tcpopt_hdr_fields {
-       TCPOPTHDR_FIELD_INVALID,
-       TCPOPTHDR_FIELD_KIND,
-       TCPOPTHDR_FIELD_LENGTH,
-       TCPOPTHDR_FIELD_SIZE,
-       TCPOPTHDR_FIELD_COUNT,
-       TCPOPTHDR_FIELD_LEFT,
-       TCPOPTHDR_FIELD_RIGHT,
-       TCPOPTHDR_FIELD_TSVAL,
-       TCPOPTHDR_FIELD_TSECR,
+/* Internal identifiers */
+enum tcpopt_common {
+       TCPOPT_COMMON_KIND,
+       TCPOPT_COMMON_LENGTH,
+};
+
+enum tcpopt_maxseg {
+       TCPOPT_MAXSEG_KIND,
+       TCPOPT_MAXSEG_LENGTH,
+       TCPOPT_MAXSEG_SIZE,
+};
+
+enum tcpopt_timestamp {
+       TCPOPT_TS_KIND,
+       TCPOPT_TS_LENGTH,
+       TCPOPT_TS_TSVAL,
+       TCPOPT_TS_TSECR,
+};
+
+enum tcpopt_windowscale {
+       TCPOPT_WINDOW_KIND,
+       TCPOPT_WINDOW_LENGTH,
+       TCPOPT_WINDOW_COUNT,
+};
+
+enum tcpopt_hdr_field_sack {
+       TCPOPT_SACK_KIND,
+       TCPOPT_SACK_LENGTH,
+       TCPOPT_SACK_LEFT,
+       TCPOPT_SACK_RIGHT,
+       TCPOPT_SACK_LEFT1,
+       TCPOPT_SACK_RIGHT1,
+       TCPOPT_SACK_LEFT2,
+       TCPOPT_SACK_RIGHT2,
+       TCPOPT_SACK_LEFT3,
+       TCPOPT_SACK_RIGHT3,
 };
 
 extern const struct exthdr_desc *tcpopt_protocols[__TCPOPT_KIND_MAX];

diff --git a/src/evaluate.c b/src/evaluate.c
index af52ab181b2987089bfb657f3a70d20b8f0c37b6..76b25b408d559558459641afaafbc146204eb775 100644 (file)
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -477,7 +477,7 @@ static void expr_evaluate_bits(struct eval_ctx *ctx, struct expr **exprp)
                                          &extra_len);
                break;
        case EXPR_EXTHDR:
-               shift = expr_offset_shift(expr, expr->exthdr.tmpl->offset,
+               shift = expr_offset_shift(expr, expr->exthdr.offset,
                                          &extra_len);
                break;
        default:
@@ -530,18 +530,16 @@ static int __expr_evaluate_exthdr(struct eval_ctx *ctx, struct expr **exprp)
        if (expr_evaluate_primary(ctx, exprp) < 0)
                return -1;
 
-       if (expr->exthdr.tmpl->offset % BITS_PER_BYTE != 0 ||
+       if (expr->exthdr.offset % BITS_PER_BYTE != 0 ||
            expr->len % BITS_PER_BYTE != 0)
                expr_evaluate_bits(ctx, exprp);
 
        switch (expr->exthdr.op) {
        case NFT_EXTHDR_OP_TCPOPT: {
                static const unsigned int max_tcpoptlen = (15 * 4 - 20) * BITS_PER_BYTE;
-               unsigned int totlen = 0;
+               unsigned int totlen;
 
-               totlen += expr->exthdr.tmpl->offset;
-               totlen += expr->exthdr.tmpl->len;
-               totlen += expr->exthdr.offset;
+               totlen = expr->exthdr.tmpl->len + expr->exthdr.offset;
 
                if (totlen > max_tcpoptlen)
                        return expr_error(ctx->msgs, expr,
@@ -551,11 +549,9 @@ static int __expr_evaluate_exthdr(struct eval_ctx *ctx, struct expr **exprp)
        }
        case NFT_EXTHDR_OP_IPV4: {
                static const unsigned int max_ipoptlen = 40 * BITS_PER_BYTE;
-               unsigned int totlen = 0;
+               unsigned int totlen;
 
-               totlen += expr->exthdr.tmpl->offset;
-               totlen += expr->exthdr.tmpl->len;
-               totlen += expr->exthdr.offset;
+               totlen = expr->exthdr.offset + expr->exthdr.tmpl->len;
 
                if (totlen > max_ipoptlen)
                        return expr_error(ctx->msgs, expr,

diff --git a/src/exthdr.c b/src/exthdr.c
index 0b23e0d38b910cca4b79dfce82e9f0975c06bb41..e1b7f14d41944327ab22c97505c9075b3d204e14 100644 (file)
--- a/src/exthdr.c
+++ b/src/exthdr.c
@@ -193,6 +193,7 @@ struct expr *exthdr_expr_alloc(const struct location *loc,
                          BYTEORDER_BIG_ENDIAN, tmpl->len);
        expr->exthdr.desc = desc;
        expr->exthdr.tmpl = tmpl;
+       expr->exthdr.offset = tmpl->offset;
        return expr;
 }
 

diff --git a/src/ipopt.c b/src/ipopt.c
index b3d0279d673ae1cd4682df60148e4b9ff27a3350..7ecb8b9c8e32a2417d5f9539bb58f48c6bda80fc 100644 (file)
--- a/src/ipopt.c
+++ b/src/ipopt.c
@@ -102,7 +102,7 @@ struct expr *ipopt_expr_alloc(const struct location *loc, uint8_t type,
        expr->exthdr.desc   = desc;
        expr->exthdr.tmpl   = tmpl;
        expr->exthdr.op     = NFT_EXTHDR_OP_IPV4;
-       expr->exthdr.offset = calc_offset(desc, tmpl, ptr);
+       expr->exthdr.offset = tmpl->offset + calc_offset(desc, tmpl, ptr);
 
        return expr;
 }

diff --git a/src/netlink_delinearize.c b/src/netlink_delinearize.c
index 32ec07a09121625b490168bded1f62741491d2e0..9faddde6397431f5452454153c768a363b86b2fc 100644 (file)
--- a/src/netlink_delinearize.c
+++ b/src/netlink_delinearize.c
@@ -809,8 +809,8 @@ static void netlink_parse_numgen(struct netlink_parse_ctx *ctx,
                                 const struct location *loc,
                                 const struct nftnl_expr *nle)
 {
-       enum nft_registers dreg;
        uint32_t type, until, offset;
+       enum nft_registers dreg;
        struct expr *expr;
 
        type  = nftnl_expr_get_u32(nle, NFTNL_EXPR_NG_TYPE);

diff --git a/src/netlink_linearize.c b/src/netlink_linearize.c
index 23cf54639303a9e758fdf9605455391bf859ab8a..a37e4b940973ba00c8431f739f3d14e6f4b239b7 100644 (file)
--- a/src/netlink_linearize.c
+++ b/src/netlink_linearize.c
@@ -200,7 +200,7 @@ static void netlink_gen_exthdr(struct netlink_linearize_ctx *ctx,
                               const struct expr *expr,
                               enum nft_registers dreg)
 {
-       unsigned int offset = expr->exthdr.tmpl->offset + expr->exthdr.offset;
+       unsigned int offset = expr->exthdr.offset;
        struct nftnl_expr *nle;
 
        nle = alloc_nft_expr("exthdr");
@@ -966,7 +966,7 @@ static void netlink_gen_exthdr_stmt(struct netlink_linearize_ctx *ctx,
 
        expr = stmt->exthdr.expr;
 
-       offset = expr->exthdr.tmpl->offset + expr->exthdr.offset;
+       offset = expr->exthdr.offset;
 
        nle = alloc_nft_expr("exthdr");
        netlink_put_register(nle, NFTNL_EXPR_EXTHDR_SREG, sreg);

diff --git a/src/parser_bison.y b/src/parser_bison.y
index fcbfb40d3ab11fb4caf86545f21f271989bcefa2..7dedbd2564b238a95ade36a039bcc1b89c79343c 100644 (file)
--- a/src/parser_bison.y
+++ b/src/parser_bison.y
@@ -5195,7 +5195,7 @@ tcp_hdr_expr              :       TCP     tcp_hdr_field
                        }
                        |       TCP     OPTION  tcp_hdr_option_type
                        {
-                               $$ = tcpopt_expr_alloc(&@$, $3, TCPOPTHDR_FIELD_KIND);
+                               $$ = tcpopt_expr_alloc(&@$, $3, TCPOPT_COMMON_KIND);
                                $$->exthdr.flags = NFT_EXTHDR_F_PRESENT;
                        }
                        ;
@@ -5226,14 +5226,14 @@ tcp_hdr_option_type     :       EOL             { $$ = TCPOPT_KIND_EOL; }
                        |       TIMESTAMP       { $$ = TCPOPT_KIND_TIMESTAMP; }
                        ;
 
-tcp_hdr_option_field   :       KIND            { $$ = TCPOPTHDR_FIELD_KIND; }
-                       |       LENGTH          { $$ = TCPOPTHDR_FIELD_LENGTH; }
-                       |       SIZE            { $$ = TCPOPTHDR_FIELD_SIZE; }
-                       |       COUNT           { $$ = TCPOPTHDR_FIELD_COUNT; }
-                       |       LEFT            { $$ = TCPOPTHDR_FIELD_LEFT; }
-                       |       RIGHT           { $$ = TCPOPTHDR_FIELD_RIGHT; }
-                       |       TSVAL           { $$ = TCPOPTHDR_FIELD_TSVAL; }
-                       |       TSECR           { $$ = TCPOPTHDR_FIELD_TSECR; }
+tcp_hdr_option_field   :       KIND            { $$ = TCPOPT_COMMON_KIND; }
+                       |       LENGTH          { $$ = TCPOPT_COMMON_LENGTH; }
+                       |       SIZE            { $$ = TCPOPT_MAXSEG_SIZE; }
+                       |       COUNT           { $$ = TCPOPT_WINDOW_COUNT; }
+                       |       LEFT            { $$ = TCPOPT_SACK_LEFT; }
+                       |       RIGHT           { $$ = TCPOPT_SACK_RIGHT; }
+                       |       TSVAL           { $$ = TCPOPT_TS_TSVAL; }
+                       |       TSECR           { $$ = TCPOPT_TS_TSECR; }
                        ;
 
 dccp_hdr_expr          :       DCCP    dccp_hdr_field

diff --git a/src/parser_json.c b/src/parser_json.c
index c68b64d9f636bb5ab5beb4c47ad4996f4d96d7af..6e1333659f81ab1d7ac33ee2f9cc449212ab7696 100644 (file)
--- a/src/parser_json.c
+++ b/src/parser_json.c
@@ -468,8 +468,10 @@ static int json_parse_tcp_option_type(const char *name, int *val)
        }
        /* special case for sack0 - sack3 */
        if (sscanf(name, "sack%u", &i) == 1 && i < 4) {
-               if (val)
-                       *val = TCPOPT_KIND_SACK + i;
+               if (val && i == 0)
+                       *val = TCPOPT_KIND_SACK;
+               else if (val && i > 0)
+                       *val = TCPOPT_KIND_SACK1 + i - 1;
                return 0;
        }
        return 1;
@@ -477,12 +479,38 @@ static int json_parse_tcp_option_type(const char *name, int *val)
 
 static int json_parse_tcp_option_field(int type, const char *name, int *val)
 {
+       const struct exthdr_desc *desc;
+       unsigned int block = 0;
        unsigned int i;
-       const struct exthdr_desc *desc = tcpopt_protocols[type];
+
+       switch (type) {
+       case TCPOPT_KIND_SACK1:
+               type = TCPOPT_KIND_SACK;
+               block = 1;
+               break;
+       case TCPOPT_KIND_SACK2:
+               type = TCPOPT_KIND_SACK;
+               block = 2;
+               break;
+       case TCPOPT_KIND_SACK3:
+               type = TCPOPT_KIND_SACK;
+               block = 3;
+               break;
+       }
+
+       if (type < 0 || type >= (int)array_size(tcpopt_protocols))
+               return 1;
+
+       desc = tcpopt_protocols[type];
 
        for (i = 0; i < array_size(desc->templates); i++) {
                if (desc->templates[i].token &&
                    !strcmp(desc->templates[i].token, name)) {
+                       if (block) {
+                               block--;
+                               continue;
+                       }
+
                        if (val)
                                *val = i;
                        return 0;
@@ -587,7 +615,7 @@ static struct expr *json_parse_tcp_option_expr(struct json_ctx *ctx,
 
        if (json_unpack(root, "{s:s}", "field", &field)) {
                expr = tcpopt_expr_alloc(int_loc, descval,
-                                        TCPOPTHDR_FIELD_KIND);
+                                        TCPOPT_COMMON_KIND);
                expr->exthdr.flags = NFT_EXTHDR_F_PRESENT;
 
                return expr;

diff --git a/src/tcpopt.c b/src/tcpopt.c
index 17cb580d0ead29a2a3eef197a0c264d32047cddf..d1dd13b868e8e54d6db1d8f8f4d450bff92e9c05 100644 (file)
--- a/src/tcpopt.c
+++ b/src/tcpopt.c
@@ -22,7 +22,7 @@ static const struct exthdr_desc tcpopt_eol = {
        .name           = "eol",
        .type           = TCPOPT_KIND_EOL,
        .templates      = {
-               [TCPOPTHDR_FIELD_KIND]          = PHT("kind",  0,    8),
+               [TCPOPT_COMMON_KIND]            = PHT("kind",  0,    8),
        },
 };
 
@@ -30,7 +30,7 @@ static const struct exthdr_desc tcpopt_nop = {
        .name           = "nop",
        .type           = TCPOPT_KIND_NOP,
        .templates      = {
-               [TCPOPTHDR_FIELD_KIND]          = PHT("kind",   0,   8),
+               [TCPOPT_COMMON_KIND]            = PHT("kind",  0,    8),
        },
 };
 
@@ -38,9 +38,9 @@ static const struct exthdr_desc tcptopt_maxseg = {
        .name           = "maxseg",
        .type           = TCPOPT_KIND_MAXSEG,
        .templates      = {
-               [TCPOPTHDR_FIELD_KIND]          = PHT("kind",   0,  8),
-               [TCPOPTHDR_FIELD_LENGTH]        = PHT("length", 8,  8),
-               [TCPOPTHDR_FIELD_SIZE]          = PHT("size",  16, 16),
+               [TCPOPT_MAXSEG_KIND]    = PHT("kind",   0,  8),
+               [TCPOPT_MAXSEG_LENGTH]  = PHT("length", 8,  8),
+               [TCPOPT_MAXSEG_SIZE]    = PHT("size",  16, 16),
        },
 };
 
@@ -48,9 +48,9 @@ static const struct exthdr_desc tcpopt_window = {
        .name           = "window",
        .type           = TCPOPT_KIND_WINDOW,
        .templates      = {
-               [TCPOPTHDR_FIELD_KIND]          = PHT("kind",   0,  8),
-               [TCPOPTHDR_FIELD_LENGTH]        = PHT("length", 8,  8),
-               [TCPOPTHDR_FIELD_COUNT]         = PHT("count", 16,  8),
+               [TCPOPT_WINDOW_KIND]    = PHT("kind",   0,  8),
+               [TCPOPT_WINDOW_LENGTH]  = PHT("length", 8,  8),
+               [TCPOPT_WINDOW_COUNT]   = PHT("count", 16,  8),
        },
 };
 
@@ -58,8 +58,8 @@ static const struct exthdr_desc tcpopt_sack_permitted = {
        .name           = "sack-perm",
        .type           = TCPOPT_KIND_SACK_PERMITTED,
        .templates      = {
-               [TCPOPTHDR_FIELD_KIND]          = PHT("kind",   0, 8),
-               [TCPOPTHDR_FIELD_LENGTH]        = PHT("length", 8, 8),
+               [TCPOPT_COMMON_KIND]    = PHT("kind",   0, 8),
+               [TCPOPT_COMMON_LENGTH]  = PHT("length", 8, 8),
        },
 };
 
@@ -67,10 +67,16 @@ static const struct exthdr_desc tcpopt_sack = {
        .name           = "sack",
        .type           = TCPOPT_KIND_SACK,
        .templates      = {
-               [TCPOPTHDR_FIELD_KIND]          = PHT("kind",   0,   8),
-               [TCPOPTHDR_FIELD_LENGTH]                = PHT("length", 8,   8),
-               [TCPOPTHDR_FIELD_LEFT]          = PHT("left",  16,  32),
-               [TCPOPTHDR_FIELD_RIGHT]         = PHT("right", 48,  32),
+               [TCPOPT_SACK_KIND]      = PHT("kind",   0,   8),
+               [TCPOPT_SACK_LENGTH]    = PHT("length", 8,   8),
+               [TCPOPT_SACK_LEFT]      = PHT("left",  16,  32),
+               [TCPOPT_SACK_RIGHT]     = PHT("right", 48,  32),
+               [TCPOPT_SACK_LEFT1]     = PHT("left",  80,  32),
+               [TCPOPT_SACK_RIGHT1]    = PHT("right", 112,  32),
+               [TCPOPT_SACK_LEFT2]     = PHT("left",  144,  32),
+               [TCPOPT_SACK_RIGHT2]    = PHT("right", 176,  32),
+               [TCPOPT_SACK_LEFT3]     = PHT("left",  208,  32),
+               [TCPOPT_SACK_RIGHT3]    = PHT("right", 240,  32),
        },
 };
 
@@ -78,12 +84,13 @@ static const struct exthdr_desc tcpopt_timestamp = {
        .name           = "timestamp",
        .type           = TCPOPT_KIND_TIMESTAMP,
        .templates      = {
-               [TCPOPTHDR_FIELD_KIND]          = PHT("kind",   0,  8),
-               [TCPOPTHDR_FIELD_LENGTH]        = PHT("length", 8,  8),
-               [TCPOPTHDR_FIELD_TSVAL]         = PHT("tsval",  16, 32),
-               [TCPOPTHDR_FIELD_TSECR]         = PHT("tsecr",  48, 32),
+               [TCPOPT_TS_KIND]        = PHT("kind",   0,  8),
+               [TCPOPT_TS_LENGTH]      = PHT("length", 8,  8),
+               [TCPOPT_TS_TSVAL]       = PHT("tsval",  16, 32),
+               [TCPOPT_TS_TSECR]       = PHT("tsecr",  48, 32),
        },
 };
+
 #undef PHT
 
 const struct exthdr_desc *tcpopt_protocols[] = {
@@ -96,65 +103,43 @@ const struct exthdr_desc *tcpopt_protocols[] = {
        [TCPOPT_KIND_TIMESTAMP]         = &tcpopt_timestamp,
 };
 
-static unsigned int calc_offset(const struct exthdr_desc *desc,
-                               const struct proto_hdr_template *tmpl,
-                               unsigned int num)
-{
-       if (!desc || tmpl == &tcpopt_unknown_template)
-               return 0;
-
-       switch (desc->type) {
-       case TCPOPT_SACK:
-               /* Make sure, offset calculations only apply to left and right
-                * fields
-                */
-               return (tmpl->offset < 16) ? 0 : num * 64;
-       default:
-               return 0;
-       }
-}
-
-
-static unsigned int calc_offset_reverse(const struct exthdr_desc *desc,
-                                       const struct proto_hdr_template *tmpl,
-                                       unsigned int offset)
-{
-       if (!desc || tmpl == &tcpopt_unknown_template)
-               return offset;
-
-       switch (desc->type) {
-       case TCPOPT_SACK:
-               /* We can safely ignore the first left/right field */
-               return offset < 80 ? offset : (offset % 64);
-       default:
-               return offset;
-       }
-}
-
 struct expr *tcpopt_expr_alloc(const struct location *loc,
                               unsigned int kind,
                               unsigned int field)
 {
        const struct proto_hdr_template *tmpl;
-       const struct exthdr_desc *desc;
-       uint8_t optnum = 0;
+       const struct exthdr_desc *desc = NULL;
        struct expr *expr;
 
        switch (kind) {
        case TCPOPT_KIND_SACK1:
                kind = TCPOPT_KIND_SACK;
-               optnum = 1;
+               if (field == TCPOPT_SACK_LEFT)
+                       field = TCPOPT_SACK_LEFT1;
+               else if (field == TCPOPT_SACK_RIGHT)
+                       field = TCPOPT_SACK_RIGHT1;
                break;
        case TCPOPT_KIND_SACK2:
                kind = TCPOPT_KIND_SACK;
-               optnum = 2;
+               if (field == TCPOPT_SACK_LEFT)
+                       field = TCPOPT_SACK_LEFT2;
+               else if (field == TCPOPT_SACK_RIGHT)
+                       field = TCPOPT_SACK_RIGHT2;
                break;
        case TCPOPT_KIND_SACK3:
                kind = TCPOPT_KIND_SACK;
-               optnum = 3;
+               if (field == TCPOPT_SACK_LEFT)
+                       field = TCPOPT_SACK_LEFT3;
+               else if (field == TCPOPT_SACK_RIGHT)
+                       field = TCPOPT_SACK_RIGHT3;
+               break;
        }
 
-       desc = tcpopt_protocols[kind];
+       if (kind < array_size(tcpopt_protocols))
+               desc = tcpopt_protocols[kind];
+
+       if (!desc)
+               return NULL;
        tmpl = &desc->templates[field];
        if (!tmpl)
                return NULL;
@@ -164,34 +149,32 @@ struct expr *tcpopt_expr_alloc(const struct location *loc,
        expr->exthdr.desc   = desc;
        expr->exthdr.tmpl   = tmpl;
        expr->exthdr.op     = NFT_EXTHDR_OP_TCPOPT;
-       expr->exthdr.offset = calc_offset(desc, tmpl, optnum);
+       expr->exthdr.offset = tmpl->offset;
 
        return expr;
 }
 
-void tcpopt_init_raw(struct expr *expr, uint8_t type, unsigned int offset,
+void tcpopt_init_raw(struct expr *expr, uint8_t type, unsigned int off,
                     unsigned int len, uint32_t flags)
 {
        const struct proto_hdr_template *tmpl;
-       unsigned int i, off;
+       unsigned int i;
 
        assert(expr->etype == EXPR_EXTHDR);
 
        expr->len = len;
        expr->exthdr.flags = flags;
-       expr->exthdr.offset = offset;
+       expr->exthdr.offset = off;
+
+       if (type >= array_size(tcpopt_protocols))
+               return;
 
-       assert(type < array_size(tcpopt_protocols));
        expr->exthdr.desc = tcpopt_protocols[type];
        expr->exthdr.flags = flags;
        assert(expr->exthdr.desc != NULL);
 
        for (i = 0; i < array_size(expr->exthdr.desc->templates); ++i) {
                tmpl = &expr->exthdr.desc->templates[i];
-               /* We have to reverse calculate the offset for the sack options
-                * at this point
-                */
-               off = calc_offset_reverse(expr->exthdr.desc, tmpl, offset);
                if (tmpl->offset != off || tmpl->len != len)
                        continue;