Re: [PATCH nft] src: osf: add ttl option support

[Fernando Fernandez Mancera]

I have not implemented tests and json support yet because I prefer to do 
it after the review of this patchset. Thanks!

On 9/16/18 9:11 PM, Fernando Fernandez Mancera wrote:
Add support for ttl option in "osf" expression. Example:
table ip foo {
        chain bar {
                type filter hook input priority filter; policy accept;
                osf ttl 0 name "Linux"
        }
}

Signed-off-by: Fernando Fernandez Mancera <ffmanc...@riseup.net>
---
  include/expression.h                |  4 ++++
  include/linux/netfilter/nf_tables.h |  2 ++
  include/osf.h                       |  2 +-
  src/netlink_delinearize.c           |  5 ++++-
  src/netlink_linearize.c             |  1 +
  src/osf.c                           | 13 +++++++++++--
  src/parser_bison.y                  |  4 ++--
  7 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/include/expression.h b/include/expression.h
index f2c5c1a..d3cca1c 100644
--- a/include/expression.h
+++ b/include/expression.h
@@ -337,6 +337,10 @@ struct expr {
                        uint32_t                flags;
                        uint32_t                result;
                } fib;
+               struct {
+                       /* EXPR_OSF */
+                       uint8_t                 ttl;
+               } osf;
        };
  };
  
diff --git a/include/linux/netfilter/nf_tables.h b/include/linux/netfilter/nf_tables.h
index 143ebe2..6c3f08c 100644
--- a/include/linux/netfilter/nf_tables.h
+++ b/include/linux/netfilter/nf_tables.h
@@ -938,10 +938,12 @@ enum nft_socket_keys {
   * enum nft_osf_attributes - nf_tables osf expression netlink attributes
   *
   * @NFTA_OSF_DREG: destination register (NLA_U32: nft_registers)
+ * @NFTA_OSF_TTL: Value of the TTL osf option (NLA_U8)
   */
  enum nft_osf_attributes {
        NFTA_OSF_UNSPEC,
        NFTA_OSF_DREG,
+       NFTA_OSF_TTL,
        __NFTA_OSF_MAX
  };
  #define NFT_OSF_MAX           (__NFTA_OSF_MAX - 1)
diff --git a/include/osf.h b/include/osf.h
index 54cdd4a..23ea34d 100644
--- a/include/osf.h
+++ b/include/osf.h
@@ -1,7 +1,7 @@
  #ifndef NFTABLES_OSF_H
  #define NFTABLES_OSF_H
  
-struct expr *osf_expr_alloc(const struct location *loc);
+struct expr *osf_expr_alloc(const struct location *loc, const uint8_t ttl);
  
  extern int nfnl_osf_load_fingerprints(struct netlink_ctx *ctx, int del);
  
diff --git a/src/netlink_delinearize.c b/src/netlink_delinearize.c
index 6c5188c..021ff7b 100644
--- a/src/netlink_delinearize.c
+++ b/src/netlink_delinearize.c
@@ -636,8 +636,11 @@ static void netlink_parse_osf(struct netlink_parse_ctx 
*ctx,
  {
        enum nft_registers dreg;
        struct expr *expr;
+       uint8_t ttl;
+
+       ttl = nftnl_expr_get_u8(nle, NFTNL_EXPR_OSF_TTL);
+       expr = osf_expr_alloc(loc, ttl);
  
-	expr = osf_expr_alloc(loc);
        dreg = netlink_parse_register(nle, NFTNL_EXPR_OSF_DREG);
        netlink_set_register(ctx, dreg, expr);
  }
diff --git a/src/netlink_linearize.c b/src/netlink_linearize.c
index 0bd946a..28f23da 100644
--- a/src/netlink_linearize.c
+++ b/src/netlink_linearize.c
@@ -227,6 +227,7 @@ static void netlink_gen_osf(struct netlink_linearize_ctx 
*ctx,
  
  	nle = alloc_nft_expr("osf");
        netlink_put_register(nle, NFTNL_EXPR_OSF_DREG, dreg);
+       nftnl_expr_set_u8(nle, NFTNL_EXPR_OSF_TTL, expr->osf.ttl);
        nftnl_rule_add_expr(ctx->nlr, nle);
  }
  
diff --git a/src/osf.c b/src/osf.c
index 85c9573..2341dfb 100644
--- a/src/osf.c
+++ b/src/osf.c
@@ -7,11 +7,17 @@
  
  static void osf_expr_print(const struct expr *expr, struct output_ctx *octx)
  {
-       nft_print(octx, "osf name");
+       nft_print(octx, "osf ttl %u name", expr->osf.ttl);
  }
  
  static void osf_expr_clone(struct expr *new, const struct expr *expr)
  {
+       new->osf.ttl = expr->osf.ttl;
+}
+
+static bool osf_expr_cmp(const struct expr *e1, const struct expr *e2)
+{
+       return e1->osf.ttl == e2->osf.ttl;
  }
  
  static const struct expr_ops osf_expr_ops = {
@@ -19,10 +25,11 @@ static const struct expr_ops osf_expr_ops = {
        .name           = "osf",
        .print          = osf_expr_print,
        .clone          = osf_expr_clone,
+       .cmp            = osf_expr_cmp,
        .json           = osf_expr_json,
  };
  
-struct expr *osf_expr_alloc(const struct location *loc)
+struct expr *osf_expr_alloc(const struct location *loc, const uint8_t ttl)
  {
        unsigned int len = NFT_OSF_MAXGENRELEN * BITS_PER_BYTE;
        const struct datatype *type = &string_type;
@@ -31,5 +38,7 @@ struct expr *osf_expr_alloc(const struct location *loc)
        expr = expr_alloc(loc, &osf_expr_ops, type,
                          BYTEORDER_HOST_ENDIAN, len);
  
+	expr->osf.ttl = ttl;
+
        return expr;
  }
diff --git a/src/parser_bison.y b/src/parser_bison.y
index 85830d8..11f8ad5 100644
--- a/src/parser_bison.y
+++ b/src/parser_bison.y
@@ -3087,9 +3087,9 @@ fib_tuple         :       fib_flag        DOT     
fib_tuple
                        |       fib_flag
                        ;
  
-osf_expr		:	OSF	NAME
+osf_expr               :       OSF     NUM     NAME
                        {
-                               $$ = osf_expr_alloc(&@$);
+                               $$ = osf_expr_alloc(&@$, $2);
                        }
                        ;