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Netlink: Simplify kernel module's Netlink core API
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Looking for #352 by code analysis, I was hampered by the cluttered
Netlink API. Managing translator instances and Netlink responses
separately lead to overcoding for no practical benefit, and managing
error messages in yet another separate module was just confusing for no
reason. (And dangerous, since it was storing the errors in a global
variable. This didn't cause any errors that I'm aware of, though.)

This centralizes all of that into a request handling state structure,
jnl_state, which lives in the heap, and which mirrors the translation
state structure. (xlation, which would benefit from a rename now.) This
leads to a better substance-to-boilerplate ratio in the Netlink
handlers.

Unfortunately, this is just developer vanity. While I certainly prefer
the new API, I didn't find #352 in the end, or any other errors for that
matter.
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@ydahhrk
ydahhrk committed Feb 18, 2021
1 parent 76929f8 commit 41e3ca6
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Showing 76 changed files with 1,715 additions and 1,924 deletions.
127 changes: 71 additions & 56 deletions src/common/global.c
View file
Original file line number Diff line number Diff line change
@@ -1,9 +1,9 @@
#include "common/global.h"

#ifdef __KERNEL__
#include "mod/common/address.h"
#include "mod/common/log.h"
#include "mod/common/nl/attribute.h"
#include "mod/common/nl/nl_common.h"
#include "mod/common/db/global.h"
#else
#include <stddef.h>
Expand All @@ -26,7 +26,8 @@ typedef int (*joolnl_global_nl2raw_fn)(
struct joolnl_global_meta const *,
struct nlattr *,
void *,
bool
bool,
struct jnl_state *
);

#else
Expand Down Expand Up @@ -127,203 +128,218 @@ static int raw2nl_mapping_rule(struct joolnl_global_meta const *meta, void *raw,
}

static int nl2raw_bool(struct joolnl_global_meta const *meta,
struct nlattr *attr, void *raw, bool force)
struct nlattr *attr, void *raw, bool force,
struct jnl_state *state)
{
*((bool *)raw) = nla_get_u8(attr);
return 0;
}

static int nl2raw_u8(struct joolnl_global_meta const *meta, struct nlattr *attr,
void *raw, bool force)
static int nl2raw_u8(struct joolnl_global_meta const *meta,
struct nlattr *attr, void *raw, bool force,
struct jnl_state *state)
{
*((__u8 *)raw) = nla_get_u8(attr);
return 0;
}

static int nl2raw_u32(struct joolnl_global_meta const *meta,
struct nlattr *attr, void *raw, bool force)
struct nlattr *attr, void *raw, bool force,
struct jnl_state *state)
{
*((__u32 *)raw) = nla_get_u32(attr);
return 0;
}

static int nl2raw_plateaus(struct joolnl_global_meta const *meta,
struct nlattr *attr, void *raw, bool force)
struct nlattr *attr, void *raw, bool force,
struct jnl_state *state)
{
return jnla_get_plateaus(attr, raw);
return jnla_get_plateaus(attr, raw, state);
}

static int validate_prefix6791v4(struct config_prefix4 *prefix, bool force)
static int validate_prefix6791v4(struct config_prefix4 *prefix, bool force,
struct jnl_state *state)
{
int error;

if (!prefix->set)
return 0;

error = prefix4_validate(&prefix->prefix);
error = prefix4_validate(&prefix->prefix, state);
if (error)
return error;

return prefix4_validate_scope(&prefix->prefix, force);
return prefix4_validate_scope(&prefix->prefix, force, state);
}

static int nl2raw_pool6(struct joolnl_global_meta const *meta,
struct nlattr *attr, void *raw, bool force)
struct nlattr *attr, void *raw, bool force,
struct jnl_state *state)
{
struct config_prefix6 *prefix = raw;
int error;

error = jnla_get_prefix6_optional(attr, meta->name, prefix);
error = jnla_get_prefix6_optional(attr, meta->name, prefix, state);
if (error)
return error;

return pool6_validate(prefix, force);
return pool6_validate(prefix, force, state);
}

static int nl2raw_prefix6(struct joolnl_global_meta const *meta,
struct nlattr *attr, void *raw, bool force)
struct nlattr *attr, void *raw, bool force,
struct jnl_state *state)
{
struct config_prefix6 *prefix = raw;
int error;

error = jnla_get_prefix6_optional(attr, meta->name, prefix);
error = jnla_get_prefix6_optional(attr, meta->name, prefix, state);
if (error)
return error;

return prefix->set ? prefix6_validate(&prefix->prefix) : 0;
return prefix->set ? prefix6_validate(&prefix->prefix, state) : 0;
}

static int nl2raw_pool6791v4(struct joolnl_global_meta const *meta,
struct nlattr *attr, void *raw, bool force)
struct nlattr *attr, void *raw, bool force,
struct jnl_state *state)
{
struct config_prefix4 *prefix = raw;
int error;

error = jnla_get_prefix4_optional(attr, meta->name, prefix);
error = jnla_get_prefix4_optional(attr, meta->name, prefix, state);
if (error)
return error;

return validate_prefix6791v4(prefix, force);
return validate_prefix6791v4(prefix, force, state);
}

static int nl2raw_lowest_ipv6_mtu(struct joolnl_global_meta const *meta,
struct nlattr *attr, void *raw, bool force)
struct nlattr *attr, void *raw, bool force,
struct jnl_state *state)
{
__u32 lim;

lim = nla_get_u32(attr);
if (lim < 1280) {
log_err("%s (%u) is too small (min: 1280).", meta->name, lim);
return -EINVAL;
return jnls_err(
state,
"%s (%u) is too small (min: 1280).",
meta->name, lim
);
}

*((__u32 *)raw) = lim;
return 0;
}

static int nl2raw_hairpin_mode(struct joolnl_global_meta const *meta,
struct nlattr *attr, void *raw, bool force)
struct nlattr *attr, void *raw, bool force,
struct jnl_state *state)
{
__u8 mode;

mode = nla_get_u8(attr);
if (mode != EHM_OFF && mode != EHM_SIMPLE && mode != EHM_INTRINSIC) {
log_err("Unknown hairpinning mode: %u", mode);
return -EINVAL;
}
if (mode != EHM_OFF && mode != EHM_SIMPLE && mode != EHM_INTRINSIC)
return jnls_err(state, "Unknown hairpinning mode: %u", mode);

*((__u8 *)raw) = mode;
return 0;
}

static int nl2raw_maptype(struct joolnl_global_meta const *meta,
struct nlattr *attr, void *raw, bool force)
struct nlattr *attr, void *raw, bool force,
struct jnl_state *state)
{
__u8 type;

type = nla_get_u8(attr);
if (type != MAPTYPE_BR && type != MAPTYPE_CE) {
log_err("Unknown MAP-T type: %u", type);
return -EINVAL;
}
if (type != MAPTYPE_BR && type != MAPTYPE_CE)
return jnls_err(state, "Unknown MAP-T type: %u", type);

*((__u8 *)raw) = type;
return 0;
}

static int validate_timeout(const char *what, __u32 timeout, unsigned int min)
static int validate_timeout(const char *what, __u32 timeout, unsigned int min,
struct jnl_state *state)
{
if (timeout < min) {
log_err("The '%s' timeout (%u) is too small. (min: %u)", what,
timeout, min);
return -EINVAL;
return jnls_err(state,
"The '%s' timeout (%u) is too small. (min: %u)",
what, timeout, min);
}

return 0;
}

static int nl2raw_ttl_udp(struct joolnl_global_meta const *meta,
struct nlattr *attr, void *raw, bool force)
struct nlattr *attr, void *raw, bool force,
struct jnl_state *state)
{
__u32 ttl;
int error;

ttl = nla_get_u32(attr);
error = validate_timeout(meta->name, ttl, 1000 * UDP_MIN);
error = validate_timeout(meta->name, ttl, 1000 * UDP_MIN, state);
if (!error)
*((__u32 *)raw) = ttl;

return error;
}

static int nl2raw_ttl_tcp_est(struct joolnl_global_meta const *meta,
struct nlattr *attr, void *raw, bool force)
struct nlattr *attr, void *raw, bool force,
struct jnl_state *state)
{
__u32 ttl;
int error;

ttl = nla_get_u32(attr);
error = validate_timeout(meta->name, ttl, 1000 * TCP_EST);
error = validate_timeout(meta->name, ttl, 1000 * TCP_EST, state);
if (!error)
*((__u32 *)raw) = ttl;

return error;
}

static int nl2raw_ttl_tcp_trans(struct joolnl_global_meta const *meta,
struct nlattr *attr, void *raw, bool force)
struct nlattr *attr, void *raw, bool force,
struct jnl_state *state)
{
__u32 ttl;
int error;

ttl = nla_get_u32(attr);
error = validate_timeout(meta->name, ttl, 1000 * TCP_TRANS);
error = validate_timeout(meta->name, ttl, 1000 * TCP_TRANS, state);
if (!error)
*((__u32 *)raw) = ttl;

return error;
}

static int nl2raw_f_args(struct joolnl_global_meta const *meta,
struct nlattr *attr, void *raw, bool force)
struct nlattr *attr, void *raw, bool force,
struct jnl_state *state)
{
__u8 f_args;

f_args = nla_get_u8(attr);
if (f_args > 0x0Fu) {
log_err("%s (%u) is out of range. (0-%u)", meta->name,
f_args, 0x0Fu);
return -EINVAL;
return jnls_err(state, "%s (%u) is out of range. (0-%u)",
meta->name, f_args, 0x0Fu);
}

*((__u8 *)raw) = f_args;
return 0;
}

static int nl2raw_mapping_rule(struct joolnl_global_meta const *meta,
struct nlattr *attr, void *raw, bool force)
struct nlattr *attr, void *raw, bool force,
struct jnl_state *state)
{
return jnla_get_mapping_rule(attr, meta->name, raw);
return jnla_get_mapping_rule(attr, meta->name, raw, state);
}

#else
Expand Down Expand Up @@ -1391,19 +1407,19 @@ void *joolnl_global_get(struct joolnl_global_meta const *meta, struct jool_globa
#ifdef __KERNEL__

int joolnl_global_raw2nl(struct joolnl_global_meta const *meta, void *raw,
struct sk_buff *skb)
struct sk_buff *skb, struct jnl_state *state)
{
if (!meta->type->raw2nl) {
log_err("The raw2nl callback of type '%s' is undefined.",
return jnls_err(state, "The raw2nl callback of type '%s' is undefined.",
meta->type->name);
return -EINVAL;
}

return meta->type->raw2nl(meta, raw, skb);
}

int joolnl_global_nl2raw(struct joolnl_global_meta const *meta,
struct nlattr *nl, void *raw, bool force)
struct nlattr *nl, void *raw, bool force,
struct jnl_state *state)
{
joolnl_global_nl2raw_fn nl2raw;

Expand All @@ -1412,12 +1428,11 @@ int joolnl_global_nl2raw(struct joolnl_global_meta const *meta,
else if (meta->type->nl2raw)
nl2raw = meta->type->nl2raw;
else {
log_err("Global '%s' has no nl2raw function, and its type doesn't either.",
return jnls_err(state, "Global '%s' has no nl2raw function, and its type doesn't either.",
meta->name);
return -EINVAL;
}

return nl2raw(meta, nl, raw, force);
return nl2raw(meta, nl, raw, force, state);
}

#else
Expand Down
7 changes: 5 additions & 2 deletions src/common/global.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,7 @@

#ifdef __KERNEL__
#include <linux/skbuff.h>
#include "mod/common/nl/nl_common.h"
#else
#include "usr/util/cJSON.h"
#include "usr/util/result.h"
Expand Down Expand Up @@ -47,14 +48,16 @@ void *joolnl_global_get(
int joolnl_global_raw2nl(
struct joolnl_global_meta const *meta,
void *raw,
struct sk_buff *skb
struct sk_buff *skb,
struct jnl_state *state
);

int joolnl_global_nl2raw(
struct joolnl_global_meta const *meta,
struct nlattr *nl,
void *raw,
bool force
bool force,
struct jnl_state *state
);

#else
Expand Down
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