datatype: Replace getnameinfo() by internal lookup table
PATCH 1/1 datatype: Replace getnameinfo() by internal lookup table
To avoid exceeding the inputs number limit of the flex scanner used.
Using port number as index, to map service names in the table, results in a very sparse table, so a new struct is needed to associate ports with names.
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The services list are all well-known and registered ports of my local /etc/services file.
include/datatype.h | 11 ++++ src/datatype.c | 159 ++++++++++++++++++++++++++++++++++++++++++++++++++--- 2 files changed, 162 insertions(+), 8 deletions(-)
include/datatype.h +11 -0
@@ -172,6 +172,17 @@ struct symbolic_constant {uint64_t value; }; +/** +* struct port_servname - port <-> service name mapping +* +* @port: port number +* @name: service name +*/ +struct port_servname { +uint16_t port; +char *name; +}; +#define SYMBOL (id, v) { .identifier = (id), .value = (v) }#define SYMBOL_LIST_END (struct symbolic_constant) { }
src/datatype.c +151 -8
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Signature · 1 line
2.7.4
Pablo Neira Ayuso
maintainerHi Elise,
Quoted 5 lines · Elise Lennion
To avoid exceeding the inputs number limit of the flex scanner used.
Using port number as index, to map service names in the table, results in a very sparse table, so a new struct is needed to associate ports with names.
Please, indicate what /etc/services you have used, ie. your linux distro version, so that info remains here for the record.
More comments below.
Quoted 37 lines
Signed-off-by Elise Lennion <[email protected]>---
The services list are all well-known and registered ports of my local
/etc/servicesfile.include/datatype.h | 11 ++++ src/datatype.c | 159 ++++++++++++++++++++++++++++++++++++++++++++++++++--- 2 files changed, 162 insertions(+), 8 deletions(-)include/datatype.h +11
-0@@ -172,6 +172,17 @@ struct symbolic_constant {uint64_t value; }; +/** +* struct port_servname - port <-> service name mapping +* +* @port: port number +* @name: service name +*/ +struct port_servname { +uint16_t port; +char *name; +}; +#define SYMBOL (id, v) { .identifier = (id), .value = (v) }#define SYMBOL_LIST_END (struct symbolic_constant) { }src/datatype.c +0
-0
src/datatype.c line 31
Quoted 4 lines
src/datatype.c +1
-0@@ -28,6 +28,156 @@#include <netinet/ip_icmp.h> +static const struct port_servname services[] = {
Given that this is long, please, place this and nft_service_lookup() under a new file, src/services.c.
src/datatype.c line 32
Quoted 1 line
src/datatype.c +1
-0+ {1, "tcpmux"}, {7, "echo"}, {9, "discard"},
We use symbol_table for these definitions instead, eg.
static const struct symbol_table icmp_code_tbl = {
...
.sym_tbl = &icmp_code_tbl,If you attach the symbol table that defines the services to the inet_service_type definition, then "nft describe tcp dport" will also display the available service names.
BTW, on a different front, the binary search in this patch is useful, you can probably integrate this into the core, I mean symbolic_constant_print(). Only problem is that we would need an explicit size in struct symbol_table, but that shouldn't be a problem. And update many spots in the code, but that should be fine. You can follow up with a patch that applies on top of this to add this binary search approach.
Thanks.