Merge branch 'manipulate-exprs' into 'master'

Add functions to iterate over the expressions of existing rules

See merge request rustwall/rustables!3

1 files changed, 54 insertions, 24 deletions

diff --git a/rustables/src/expr/log.rs b/rustables/src/expr/log.rs
index aa7a8b7..db96ba9 100644
--- a/rustables/src/expr/log.rs
+++ b/rustables/src/expr/log.rs
@@ -1,34 +1,54 @@
-use super::{Expression, Rule};
+use super::{DeserializationError, Expression, Rule};
 use rustables_sys as sys;
+use std::ffi::{CStr, CString};
 use std::os::raw::c_char;
-use std::ffi::CString;
 use thiserror::Error;
 
 /// A Log expression will log all packets that match the rule.
+#[derive(Debug, PartialEq)]
 pub struct Log {
     pub group: Option<LogGroup>,
-    pub prefix: Option<LogPrefix>
+    pub prefix: Option<LogPrefix>,
 }
 
 impl Expression for Log {
-    fn to_expr(&self, _rule: &Rule) -> *mut sys::nftnl_expr {
+    fn get_raw_name() -> *const sys::libc::c_char {
+        b"log\0" as *const _ as *const c_char
+    }
+
+    fn from_expr(expr: *const sys::nftnl_expr) -> Result<Self, DeserializationError>
+    where
+        Self: Sized,
+    {
         unsafe {
-            let expr = try_alloc!(sys::nftnl_expr_alloc(
-                b"log\0" as *const _ as *const c_char
-            ));
-            if let Some(log_group) = self.group {
-                sys::nftnl_expr_set_u32(
+            let mut group = None;
+            if sys::nftnl_expr_is_set(expr, sys::NFTNL_EXPR_LOG_GROUP as u16) {
+                group = Some(LogGroup(sys::nftnl_expr_get_u32(
                     expr,
                     sys::NFTNL_EXPR_LOG_GROUP as u16,
-                    log_group.0 as u32,
-                );
+                ) as u16));
+            }
+            let mut prefix = None;
+            if sys::nftnl_expr_is_set(expr, sys::NFTNL_EXPR_LOG_PREFIX as u16) {
+                let raw_prefix = sys::nftnl_expr_get_str(expr, sys::NFTNL_EXPR_LOG_PREFIX as u16);
+                if raw_prefix.is_null() {
+                    return Err(DeserializationError::NullPointer);
+                } else {
+                    prefix = Some(LogPrefix(CStr::from_ptr(raw_prefix).to_owned()));
+                }
+            }
+            Ok(Log { group, prefix })
+        }
+    }
+
+    fn to_expr(&self, _rule: &Rule) -> *mut sys::nftnl_expr {
+        unsafe {
+            let expr = try_alloc!(sys::nftnl_expr_alloc(b"log\0" as *const _ as *const c_char));
+            if let Some(log_group) = self.group {
+                sys::nftnl_expr_set_u32(expr, sys::NFTNL_EXPR_LOG_GROUP as u16, log_group.0 as u32);
             };
             if let Some(LogPrefix(prefix)) = &self.prefix {
-                sys::nftnl_expr_set_str(
-                    expr,
-                    sys::NFTNL_EXPR_LOG_PREFIX as u16,
-                    prefix.as_ptr()
-                );
+                sys::nftnl_expr_set_str(expr, sys::NFTNL_EXPR_LOG_PREFIX as u16, prefix.as_ptr());
             };
 
             expr
@@ -41,8 +61,7 @@ pub enum LogPrefixError {
     #[error("The log prefix string is more than 128 characters long")]
     TooLongPrefix,
     #[error("The log prefix string contains an invalid Nul character.")]
-    PrefixContainsANul(#[from] std::ffi::NulError)
-
+    PrefixContainsANul(#[from] std::ffi::NulError),
 }
 
 /// The NFLOG group that will be assigned to each log line.
@@ -58,25 +77,36 @@ impl LogPrefix {
     /// that LogPrefix should not be more than 127 characters long.
     pub fn new(prefix: &str) -> Result<Self, LogPrefixError> {
         if prefix.chars().count() > 127 {
-            return Err(LogPrefixError::TooLongPrefix)
+            return Err(LogPrefixError::TooLongPrefix);
         }
         Ok(LogPrefix(CString::new(prefix)?))
     }
 }
 
-
 #[macro_export]
 macro_rules! nft_expr_log {
     (group $group:ident prefix $prefix:expr) => {
-        $crate::expr::Log { group: $group, prefix: $prefix }
+        $crate::expr::Log {
+            group: $group,
+            prefix: $prefix,
+        }
     };
     (prefix $prefix:expr) => {
-        $crate::expr::Log { group: None, prefix: $prefix }
+        $crate::expr::Log {
+            group: None,
+            prefix: $prefix,
+        }
     };
     (group $group:ident) => {
-        $crate::expr::Log { group: $group, prefix: None }
+        $crate::expr::Log {
+            group: $group,
+            prefix: None,
+        }
     };
     () => {
-        $crate::expr::Log { group: None, prefix: None }
+        $crate::expr::Log {
+            group: None,
+            prefix: None,
+        }
     };
 }