improve models and use better nft lib

backend/src/api/nftables_api.py

@@ -1,28 +1,28 @@
+# fastapi_nft_stateless_comment_enums.py
 """
-Stateless FastAPI nftables router that uses libnftables binding.
+Stateless FastAPI nftables router using pyroute2.nftables.
-
-- GET  /nft/rules  -> reconstruct rule objects from nft kernel state (best-effort)
-- PUT  /nft/rules  -> replace entire ordered ruleset (applies via binding, line-by-line)
 
+- Stateless: no in-process or on-disk rule store.
+- Rules may include an optional 'comment' field that will be written into nft's comment.
+- Enums introduced for Action.type, ip_proto (common names) and family.
+- Endpoints:
+  - GET  /nft/rules   -> reconstruct rules from kernel (returns comment if present)
+  - PUT  /nft/rules   -> replace entire ordered rule set (clients supply optional comment per rule)
 """
 from fastapi import APIRouter, HTTPException, Header, Request
 from pydantic import BaseModel, Field
-from typing import Optional, List, Dict, Any
+from typing import Optional, List, Dict, Any, Union
-import uuid
-import json
-import tempfile
-import os
 import logging
+import json
+import uuid
+from enum import Enum
 
-# try import libnftables binding
+# pyroute2 nftables
-try:
+from pyroute2 import nftables
-    from nftables import Nftables
-except Exception:
-    Nftables = None  # clearer error raised when attempting to use binding
 
 router = APIRouter(prefix="/nft", tags=["nftables"])
 logger = logging.getLogger("nftables")
-logger.debug("nftables stateless router module loaded")
+logger.debug("nftables stateless-comment-enums router loaded")
 
 # Defaults and version token
 DEFAULT_TABLE = "mitm_tbl"
@@ -30,30 +30,54 @@ DEFAULT_CHAIN = "forward"
 DEFAULT_FAMILY = "bridge"
 _current_version: Optional[str] = None
 
+
+# ---------------------- Enums ----------------------
+class ActionType(str, Enum):
+    DROP = "drop"
+    ACCEPT = "accept"
+    QUEUE = "queue"
+    REDIRECT = "redirect"
+
+
+class Protocol(str, Enum):
+    ICMP = "icmp"
+    TCP = "tcp"
+    UDP = "udp"
+
+
+class Family(str, Enum):
+    BRIDGE = "bridge"
+    INET = "inet"
+    IP = "ip"
+    IP6 = "ip6"
+    ARP = "arp"
+
+
 # ---------------------- Pydantic models ----------------------
 class MatchModel(BaseModel):
     iif: Optional[str] = None
     oif: Optional[str] = None
-    meta_length: Optional[Any] = None  # int or range string like "100-200"
+    meta_length: Optional[Any] = None  # int or range string
-    ip_proto: Optional[Any] = None     # numeric or name
+    # ip_proto may be Protocol enum, integer or arbitrary string (name)
+    ip_proto: Optional[Union[int, Protocol, str]] = None
     tcp_dport: Optional[int] = None
     udp_dport: Optional[int] = None
 
 
 class ActionModel(BaseModel):
-    type: Optional[str] = None  # drop | accept | queue | redirect
+    type: ActionType  # ActionType enum
     queue_num: Optional[int] = None
     redirect_port: Optional[int] = None
 
 
 class RuleModel(BaseModel):
-    # id is optional client-side convenience only (not persisted)
+    id: Optional[str] = Field(None, description="optional client id; not persisted")
-    id: Optional[str] = Field(None, description="optional client id; not stored server-side")
+    family: Optional[Family] = Field(Family.BRIDGE)
-    family: Optional[str] = Field(DEFAULT_FAMILY)
     table: Optional[str] = Field(DEFAULT_TABLE)
     chain: Optional[str] = Field(DEFAULT_CHAIN)
     match: MatchModel
     action: ActionModel
+    comment: Optional[str] = Field(None, description="optional human-readable comment stored in nft comment")
 
 
 class ReplaceResult(BaseModel):
@@ -62,216 +86,210 @@ class ReplaceResult(BaseModel):
     rules_count: int
 
 
-# ---------------------- nft binding helpers ----------------------
+# ---------------------- nft wrapper ----------------------
-def _ensure_binding_available():
+class NFT:
-    if Nftables is None:
+    def __init__(self):
-        raise RuntimeError(
+        self.nft = nftables.NFTables()
-            "python nftables binding not available. Install system package `python3-nftables` or a compatible binding."
-        )
 
-
+    def run(self, cmd: str) -> Dict[str, Any]:
-def nft_cmd(cmd: str):
+        """
-    """
+        Run a single nft command string via pyroute2.NFTables.cmd.
-    Run a libnftables command string.
+        Returns parsed JSON if possible, otherwise a dict with 'out' textual output.
-    Returns tuple (rc, stdout, stderr) as strings. Raises RuntimeError on unexpected binding error.
+        Raises RuntimeError on failure.
-    """
+        """
-    _ensure_binding_available()
-    nft = Nftables()
-    try:
-        rc, out, err = nft.cmd(cmd)
-        # ensure we work with strings
-        if isinstance(out, bytes):
-            out = out.decode(errors="ignore")
-        if isinstance(err, bytes):
-            err = err.decode(errors="ignore")
-        return rc, out or "", err or ""
-    except Exception as e:
-        logger.exception("unexpected nft binding exception for cmd=%s", cmd)
-        raise RuntimeError(f"nft binding error: {e}")
-
-
-def nft_run_or_raise(cmd: str) -> str:
-    """
-    Run command via binding and raise RuntimeError if rc != 0.
-    Returns stdout string on success.
-    """
-    rc, out, err = nft_cmd(cmd)
-    logger.debug("nft cmd: %s -> rc=%s out_len=%d err_len=%d", cmd, rc, len(out), len(err))
-    if rc != 0:
-        # surface err if available, otherwise a generic message
-        raise RuntimeError(err or f"nft command '{cmd}' failed (rc={rc})")
-    return out
-
-
-# ---------------------- chain/table ensure / reconstruction ----------------------
-def ensure_table_chain(family: str, table: str, chain: str) -> None:
-    """
-    Ensure the nft table and chain exist. Use libnftables `add` commands first; on failure
-    attempt to apply a tiny script by invoking individual commands (no "-f" with the binding).
-    Raises RuntimeError on persistent failure.
-    """
-    logger.info("ensuring table %s.%s exists", family, table)
-
-    # try add table
-    try:
-        nft_run_or_raise(f"add table {family} {table}")
-        logger.debug("created table %s.%s via add table", family, table)
-    except RuntimeError as e_table:
-        logger.info("add table failed: %s. attempting fallback", e_table)
-        # fallback: build script and apply the lines individually
-        script_lines = [f"table {family} {table} {{ }}"]
         try:
-            for ln in script_lines:
+            rc, out, err = self.nft.cmd(cmd)
-                nft_run_or_raise(ln)
+            if isinstance(out, bytes):
-            logger.debug("created table %s.%s via fallback lines", family, table)
+                out = out.decode(errors="ignore")
-        except RuntimeError as e2:
+            if isinstance(err, bytes):
-            logger.error("fallback for creating table failed: %s (original: %s)", e2, e_table)
+                err = err.decode(errors="ignore")
-            raise RuntimeError(f"failed to create nft table {family}.{table}: {e2}") from e2
+            if rc != 0:
-
+                raise RuntimeError(err or f"nft cmd failed rc={rc}")
-    # try add chain
+            if out:
-    logger.info("ensuring chain %s in table %s exists", chain, table)
-    try:
-        nft_run_or_raise(
-            f'add chain {family} {table} {chain} {{ type filter hook forward priority 0; policy accept; }}'
-        )
-        logger.debug("created chain %s in %s.%s via add chain", chain, family, table)
-    except RuntimeError as e_chain:
-        logger.info("add chain failed: %s. attempting fallback", e_chain)
-        script_lines = [
-            f"table {family} {table} {{",
-            f"  chain {chain} {{ type filter hook forward priority 0; policy accept; }}",
-            f"}}",
-        ]
-        try:
-            for ln in script_lines:
-                nft_run_or_raise(ln)
-            logger.debug("created chain %s in %s.%s via fallback lines", chain, family, table)
-        except RuntimeError as e2:
-            logger.error("fallback for creating chain failed: %s (original: %s)", e2, e_chain)
-            raise RuntimeError(f"failed to create nft chain {chain} in {family}.{table}: {e2}") from e2
-
-    logger.info("table/chain ensured: %s.%s/%s", family, table, chain)
-
-
-# ---------------------- reconstruct rules from nft JSON (best-effort) ----------------------
-# Replace your previous _reconstruct_rule_from_exprs and list_rules_from_nft with these.
-
-def _extract_immediate_value(node):
-    """Return an integer/string value from various immediate/data shapes, or None."""
-    if not node or not isinstance(node, dict):
-        return None
-    # common keys used by libnftables JSON
-    for k in ("immediate", "value", "data", "s", "v"):
-        if k in node:
-            val = node[k]
-            # hex strings like "0x00000050"
-            if isinstance(val, str) and val.startswith("0x"):
                 try:
-                    return int(val, 16)
+                    return json.loads(out)
                 except Exception:
-                    return val
+                    return {"out": out}
-            return val
+            return {}
-    # sometimes immediate sits under {"immediate": {"value": ...}}
+        except AttributeError:
-    if "right" in node or "left" in node:
+            # Try json_cmd fallback if older pyroute2 version
-        # caller handles left/right structures
+            out = self.nft.json_cmd(cmd)
-        return None
+            return out or {}
+        except Exception as e:
+            logger.exception("nft wrapper error for cmd=%s: %s", cmd, e)
+            raise
+
+    def add_table(self, family: str, table: str):
+        return self.run(f"add table {family} {table}")
+
+    def add_chain(self, family: str, table: str, chain: str, type_: str = "filter", hook: str = "forward", priority: int = 0, policy: str = "accept"):
+        return self.run(f'add chain {family} {table} {chain} {{ type {type_} hook {hook} priority {priority}; policy {policy}; }}')
+
+    def list_table(self, family: str, table: str):
+        return self.run(f"list table {family} {table}")
+
+    def list_chain(self, family: str, table: str, chain: str):
+        return self.run(f"list chain {family} {table} {chain} -a")
+
+    def add_rule(self, family: str, table: str, chain: str, rule_fragment: str):
+        return self.run(f"add rule {family} {table} {chain} {rule_fragment}")
+
+    def delete_rule_by_handle(self, family: str, table: str, chain: str, handle: str):
+        return self.run(f"delete rule {family} {table} {chain} handle {handle}")
+
+
+NFTC = NFT()
+
+
+# ---------------------- builders / parsers ----------------------
+def build_match_frag(match: MatchModel) -> List[str]:
+    frag: List[str] = []
+    if match.iif:
+        frag += ["iif", f'"{match.iif}"']
+    if match.oif:
+        frag += ["oif", f'"{match.oif}"']
+    if match.meta_length is not None:
+        frag += ["meta", "length", str(match.meta_length)]
+    if match.ip_proto is not None:
+        # ip_proto can be Protocol enum, int or str
+        if isinstance(match.ip_proto, Protocol):
+            frag += ["ip", "protocol", match.ip_proto.value]
+        elif isinstance(match.ip_proto, int):
+            frag += ["ip", "protocol", str(match.ip_proto)]
+        else:
+            frag += ["ip", "protocol", str(match.ip_proto)]
+    if match.tcp_dport:
+        frag += ["tcp", "dport", str(match.tcp_dport)]
+    if match.udp_dport:
+        frag += ["udp", "dport", str(match.udp_dport)]
+    return frag
+
+
+def build_action_frag(action: ActionModel) -> List[str]:
+    # ActionModel.type is an ActionType enum
+    if action.type == ActionType.DROP:
+        return ["drop"]
+    if action.type == ActionType.ACCEPT:
+        return ["accept"]
+    if action.type == ActionType.QUEUE:
+        num = action.queue_num if action.queue_num is not None else 0
+        return ["queue", "num", str(num)]
+    if action.type == ActionType.REDIRECT:
+        if action.redirect_port is None:
+            raise ValueError("redirect action requires redirect_port")
+        return ["redirect", "to", f":{action.redirect_port}"]
+    raise ValueError(f"unsupported action type: {action.type}")
+
+
+def nft_rule_fragment_from_model(rule: RuleModel) -> str:
+    """
+    Build fragment after 'add rule <family> <table> <chain>'.
+    Includes comment if rule.comment provided.
+    """
+    match_frag = build_match_frag(rule.match)
+    action_frag = build_action_frag(rule.action)
+    parts = match_frag + action_frag
+    if rule.comment:
+        # include comment as-is (user-provided). Wrap in quotes.
+        parts += ['comment', f'"{rule.comment}"']
+    return " ".join(parts)
+
+
+def parse_comment_from_exprs(exprs: List[Dict[str, Any]]) -> Optional[str]:
+    """Scan expressions for a comment expression and return its string if present."""
+    for e in exprs:
+        if "comment" in e:
+            cm = e["comment"]
+            if isinstance(cm, dict):
+                return cm.get("string") or cm.get("s") or cm.get("value")
+            elif isinstance(cm, str):
+                return cm
     return None
 
 
-def _reconstruct_rule_from_exprs(exprs: List[Dict[str, Any]]) -> Dict[str, Any]:
+def reconstruct_rule_from_rule_entry(entry: Dict[str, Any]) -> Dict[str, Any]:
     """
-    Improved best-effort mapping from nft expression JSON to our RuleModel fields.
+    Given a rule entry returned by NFTC.list_table, return a dict that resembles RuleModel
-    This function attempts to match many of the shapes produced by libnftables.
+    (family/table/chain + match + action + comment if present). This is best-effort parsing.
     """
+    # normalize expressions
+    exprs = []
+    if "rule" in entry:
+        r = entry["rule"]
+        exprs = r.get("expr") or r.get("expressions") or r.get("exprs") or []
+        chain_name = r.get("chain") or entry.get("chain") or r.get("chain_name")
+        family = entry.get("family") or DEFAULT_FAMILY
+        table = entry.get("table") or DEFAULT_TABLE
+    else:
+        exprs = entry.get("expr") or entry.get("expressions") or entry.get("exprs") or []
+        chain_name = entry.get("chain") or entry.get("chain_name")
+        family = entry.get("family") or DEFAULT_FAMILY
+        table = entry.get("table") or DEFAULT_TABLE
+
+    if isinstance(exprs, dict):
+        exprs = [exprs]
+
+    comment = parse_comment_from_exprs(exprs)
+
+    # best-effort reconstruction of match & action
     match: Dict[str, Any] = {}
     action: Dict[str, Any] = {}
 
-    # Track last payload hint (if present) so that subsequent cmp can be interpreted
+    for e in exprs:
-    last_payload_hint: Optional[Dict[str, Any]] = None
-
-    for idx, e in enumerate(exprs):
-        # handle meta (iif/oif/length)
         if "meta" in e:
             m = e["meta"]
             key = m.get("key") or m.get("type") or m.get("field")
             v = m.get("v") or m.get("s") or m.get("value")
-            # sometimes v is dict
             if isinstance(v, dict):
-                v = _extract_immediate_value(v) or v.get("s") or v.get("v")
+                v = v.get("value") or v.get("v") or v.get("s")
-            if key in ("iifname", "iif", "in", "iifname?"):
+            if key in ("iifname", "iif", "in"):
-                if v:
+                match["iif"] = v
-                    match["iif"] = v
             elif key in ("oifname", "oif", "out"):
-                if v:
+                match["oif"] = v
-                    match["oif"] = v
             elif key in ("length", "len"):
-                if v is not None:
+                match["meta_length"] = v
-                    match["meta_length"] = v
-            else:
-                logger.debug("meta with unknown key: %s value=%s", key, v)
-
-        # store payload hints for later comparisons
-        elif "payload" in e:
-            last_payload_hint = e["payload"]
-            # make it easier for cmp handling: include index
-            last_payload_hint["_idx"] = idx
-
-        # cmp (compare) expressions: left/right might be payload / immediate structures
         elif "cmp" in e or "match" in e:
             cmp_obj = e.get("cmp") or e.get("match") or {}
             left = cmp_obj.get("left")
             right = cmp_obj.get("right")
-            # extract immediate numeric if present
+            def _extract_immediate(x):
-            imm_left = _extract_immediate_value(left)
+                if not x or not isinstance(x, dict):
-            imm_right = _extract_immediate_value(right)
+                    return None
-            imm = imm_left if imm_left is not None else imm_right
+                for k in ("immediate", "value", "data", "s", "v"):
-
+                    if k in x:
-            # If either immediate is a small int treat as ip_proto
+                        val = x[k]
-            if isinstance(imm, int) and 0 < imm < 256:
+                        if isinstance(val, str) and val.startswith("0x"):
-                # prefer to store as number (frontend may show numeric)
+                            try:
-                match["ip_proto"] = imm
+                                return int(val, 16)
-
+                            except Exception:
-            # If immediate looks like port (1-65535), try to detect target (tcp/udp)
+                                return val
-            if isinstance(imm, int) and 0 < imm <= 65535:
+                        return val
-                assigned = False
+                return None
-                # heuristics: if left/right contains a payload hint referring to TCP/UDP or 'dport' strings:
+            imm = _extract_immediate(left) or _extract_immediate(right)
-                for side in (left, right):
+            if isinstance(imm, str):
-                    if isinstance(side, dict):
+                low = imm.lower()
-                        # payload form used by libnftables can include 'protocol' or 'field'
+                if low == "icmp":
-                        pl = side.get("payload") or side.get("left", {}).get("payload")
+                    match["ip_proto"] = 1
-                        if isinstance(pl, dict):
+                elif low == "tcp":
-                            protocol_hint = pl.get("protocol") or pl.get("proto") or pl.get("family")
+                    match["ip_proto"] = 6
-                            field_hint = pl.get("field") or pl.get("meta")
+                elif low == "udp":
-                            sh = json.dumps(pl).lower()
+                    match["ip_proto"] = 17
-                            if "tcp" in sh or "sport" in sh or "dport" in sh or "th" in sh:
+                else:
-                                match["tcp_dport"] = imm
+                    try:
-                                assigned = True
+                        match["ip_proto"] = int(imm)
-                                break
+                    except Exception:
-                            if "udp" in sh or "udph" in sh or "udp." in sh:
+                        match["ip_proto"] = imm
-                                match["udp_dport"] = imm
+            if isinstance(imm, int):
-                                assigned = True
+                if 0 < imm < 256:
-                                break
+                    match["ip_proto"] = imm
-                if not assigned:
+                elif 0 < imm <= 65535:
-                    # fallback: if ip_proto already indicates tcp(6) or udp(17), assign accordingly
+                    match.setdefault("tcp_dport", imm)
-                    proto = match.get("ip_proto")
-                    if proto in (6, "tcp"):
-                        match["tcp_dport"] = imm
-                    elif proto in (17, "udp"):
-                        match["udp_dport"] = imm
-                    else:
-                        # if we can't know, default to tcp_dport as most common case
-                        match.setdefault("tcp_dport", imm)
-
-        # verdict / immediate verdict expressions -> action
         elif "verdict" in e or "immediate" in e or "return" in e:
-            # verdict may be string or dict
             v = e.get("verdict") or e.get("return") or e.get("immediate")
-            # normalize dict forms
             if isinstance(v, dict):
                 t = v.get("type") or v.get("kind") or v.get("verdict")
                 if t:
                     action["type"] = t
-                # redirect/queue shaped differently across versions
                 if "to" in v:
                     action["type"] = "redirect"
                     action["redirect_port"] = v.get("to")
@@ -279,103 +297,128 @@ def _reconstruct_rule_from_exprs(exprs: List[Dict[str, Any]]) -> Dict[str, Any]:
                     action["type"] = "queue"
                     action["queue_num"] = v.get("queue")
             elif isinstance(v, str):
-                # strings like "accept" or "drop"
                 action["type"] = v
-            else:
-                # sometimes verdict is expressed as nested dict under 'verdict': {'kind':'accept'}
-                if isinstance(e.get("verdict"), dict):
-                    vv = e["verdict"]
-                    action["type"] = vv.get("kind") or vv.get("type")
-
-        # old-style 'match' entries with left/right payload/immediate
-        elif "match" in e:
-            m = e["match"]
-            left = m.get("left")
-            right = m.get("right")
-            imm_left = _extract_immediate_value(left)
-            imm_right = _extract_immediate_value(right)
-            if isinstance(imm_left, int) and 0 < imm_left < 256:
-                match["ip_proto"] = imm_left
-            if isinstance(imm_right, int) and 0 < imm_right < 256:
-                match["ip_proto"] = imm_right
-
         else:
-            # unknown expression type: log (DEBUG) for later tuning
+            # ignore other expression types
-            logger.debug("unhandled nft expr type: %s", list(e.keys()))
+            pass
 
-    # default action to accept if kernel default or none found
     if "type" not in action:
         action["type"] = "accept"
 
-    return {"match": match, "action": action}
+    # convert action.type to ActionType enum if possible
-
-
-def list_rules_from_nft(family: str, table: str) -> List[Dict[str, Any]]:
-    """
-    Reconstruct rules using libnftables JSON output with more robust parsing.
-    """
-    # ensure binding present and request JSON output explicitly
-    _ensure_binding_available()
-    nft = Nftables()
-    nft.set_json_output(True)
-    rc, out, err = nft.cmd(f"list table {family} {table}")
-    if rc != 0:
-        logger.debug("nft list table returned rc=%s err=%s", rc, err)
-        return []
-
     try:
-        data = json.loads(out)
+        action_type_val = action.get("type")
+        if isinstance(action_type_val, str):
+            action["type"] = ActionType(action_type_val)
+    except Exception:
+        # leave as-is if conversion fails
+        pass
+
+    # convert family to Family enum if possible
+    try:
+        if isinstance(family, str):
+            family = Family(family)
+    except Exception:
+        pass
+
+    return {
+        "family": family,
+        "table": table,
+        "chain": chain_name or DEFAULT_CHAIN,
+        "match": match,
+        "action": action,
+        "comment": comment,
+    }
+
+
+# ---------------------- high-level operations ----------------------
+def ensure_table_chain(family: Union[str, Family], table: str, chain: str):
+    fam = family.value if isinstance(family, Family) else family
+    try:
+        NFTC.add_table(fam, table)
     except Exception as e:
-        logger.error("failed to parse nft JSON output: %s", e)
+        logger.debug("add_table may have failed/exists: %s", e)
+    try:
+        NFTC.add_chain(fam, table, chain)
+    except Exception as e:
+        logger.debug("add_chain may have failed/exists: %s", e)
+
+
+def list_rules_from_nft(family: Union[str, Family], table: str) -> List[Dict[str, Any]]:
+    fam = family.value if isinstance(family, Family) else family
+    try:
+        out = NFTC.list_table(fam, table)
+    except Exception as e:
+        logger.debug("list_table failed: %s", e)
         return []
 
+    entries = []
+    if isinstance(out, dict) and "nftables" in out:
+        entries = out["nftables"]
+    elif isinstance(out, dict) and "out" in out and isinstance(out["out"], str):
+        try:
+            parsed = json.loads(out["out"])
+            if isinstance(parsed, dict) and "nftables" in parsed:
+                entries = parsed["nftables"]
+            elif isinstance(parsed, list):
+                entries = parsed
+        except Exception:
+            logger.debug("could not parse textual nft output")
+            entries = []
+    elif isinstance(out, list):
+        entries = out
+    elif isinstance(out, dict) and out:
+        entries = [out]
+    else:
+        entries = []
+
     results: List[Dict[str, Any]] = []
-    for item in data.get("nftables", []):
+    for item in entries:
-        if "rule" not in item:
+        if not item:
             continue
-        rule_obj = item["rule"]
+        if "rule" in item:
-        # different versions might use 'expr', 'expressions' or 'expr'
+            rule_entry = {"rule": item["rule"], "family": item.get("family"), "table": item.get("table")}
-        exprs = rule_obj.get("expr") or rule_obj.get("exprs") or rule_obj.get("expressions") or []
+        else:
-        # if exprs is not a list but a dict (some shaped outputs) normalize
+            rule_entry = item
-        if isinstance(exprs, dict):
+        reconstructed = reconstruct_rule_from_rule_entry(rule_entry)
-            # sometimes expressions are nested inside a single dict; try to find array keys
+        results.append(reconstructed)
-            for k in ("expr", "expressions", "exprs"):
-                v = exprs.get(k)
-                if isinstance(v, list):
-                    exprs = v
-                    break
-            else:
-                # give up and wrap
-                exprs = [exprs]
 
-        recon = _reconstruct_rule_from_exprs(exprs)
-        chain_name = rule_obj.get("chain") or rule_obj.get("chain_name") or rule_obj.get("table") or DEFAULT_CHAIN
-        # make output match your RuleModel-ish structure (no id)
-        rule_dict = {
-            "family": family,
-            "table": table,
-            "chain": chain_name,
-            "match": recon.get("match", {}),
-            "action": recon.get("action", {}),
-        }
-        results.append(rule_dict)
-
-    logger.debug("reconstructed %d rules from %s.%s", len(results), family, table)
     return results
 
 
+def add_rules_replace_all(rules: List[RuleModel], family: Union[str, Family], table: str, chain: str):
+    fam = family.value if isinstance(family, Family) else family
+    # flush chain
+    try:
+        NFTC.run(f"flush chain {fam} {table} {chain}")
+    except Exception as e:
+        logger.debug("flush chain may have returned error: %s", e)
+
+    # add rules
+    for r in rules:
+        # ensure family value converted to string
+        fam_r = r.family.value if isinstance(r.family, Family) else r.family
+        frag = nft_rule_fragment_from_model(r)
+        try:
+            NFTC.add_rule(fam_r, r.table, r.chain, frag)
+            logger.info("added rule frag=%s", frag)
+        except Exception as e:
+            logger.exception("failed to add rule: %s", e)
+            raise RuntimeError(f"failed to add rule: {e}")
+
 
 # ---------------------- API endpoints ----------------------
 @router.get("/rules")
-def get_rules(family: Optional[str] = DEFAULT_FAMILY, table: Optional[str] = DEFAULT_TABLE, chain: Optional[str] = DEFAULT_CHAIN):
+def get_rules(family: Optional[Union[str, Family]] = DEFAULT_FAMILY, table: Optional[str] = DEFAULT_TABLE, chain: Optional[str] = DEFAULT_CHAIN):
-    logger.debug("GET /nft/rules called (family=%s table=%s chain=%s)", family, table, chain)
+    fam = family.value if isinstance(family, Family) else family
+    logger.debug("GET /nft/rules called (family=%s table=%s chain=%s)", fam, table, chain)
     try:
-        ensure_table_chain(family, table, chain)
+        ensure_table_chain(fam, table, chain)
-    except RuntimeError as e:
+    except Exception as e:
-        logger.error("failed to ensure table/chain %s.%s/%s: %s", family, table, chain, e)
+        logger.error("failed to ensure table/chain: %s", e)
-        raise HTTPException(status_code=500, detail=f"failed to ensure nft table/chain: {e}")
+        raise HTTPException(status_code=500, detail=str(e))
 
-    rules = list_rules_from_nft(family, table)
+    rules = list_rules_from_nft(fam, table)
     return {"count": len(rules), "rules": rules, "version": _current_version}
 
 
@@ -384,107 +427,46 @@ def put_rules(
     rules: List[RuleModel],
     request: Request,
     if_match: Optional[str] = Header(None, alias="If-Match"),
-    family: Optional[str] = DEFAULT_FAMILY,
+    family: Optional[Union[str, Family]] = DEFAULT_FAMILY,
     table: Optional[str] = DEFAULT_TABLE,
     chain: Optional[str] = DEFAULT_CHAIN,
 ):
-    """
-    Replace entire ordered ruleset. Validates provided rules, then builds nft commands
-    and applies them line-by-line via libnftables binding (no '-f' token passed into binding).
-    """
-    # optimistic concurrency
     global _current_version
+    fam = family.value if isinstance(family, Family) else family
+
+    # optimistic concurrency
     if if_match is not None and _current_version is not None and if_match != _current_version:
         raise HTTPException(status_code=409, detail="version mismatch; fetch latest rules and retry")
 
-    # validate per-rule family/table/chain (quick checks)
+    # validate per-rule family/table/chain
     for r in rules:
-        if r.family and r.family != family:
+        r_family_val = r.family.value if isinstance(r.family, Family) else r.family
-            raise HTTPException(status_code=400, detail=f"rule family mismatch: {r.family} != {family}")
+        if r.family and r_family_val != fam:
+            raise HTTPException(status_code=400, detail=f"rule family mismatch: {r_family_val} != {fam}")
         if r.table and r.table != table:
             raise HTTPException(status_code=400, detail=f"rule table mismatch: {r.table} != {table}")
         if r.chain and r.chain != chain:
             raise HTTPException(status_code=400, detail=f"rule chain mismatch: {r.chain} != {chain}")
 
-    # ensure table/chain exist first
+    # ensure table/chain exist
     try:
-        ensure_table_chain(family, table, chain)
+        ensure_table_chain(fam, table, chain)
-    except RuntimeError as e:
+    except Exception as e:
         logger.error("failed to ensure table/chain: %s", e)
         raise HTTPException(status_code=500, detail=str(e))
 
-    # build script lines (flush + ordered add rules)
+    # ensure rule ids for client convenience
-    script_lines: List[str] = []
-    script_lines.append(f"flush chain {family} {table} {chain}")
-
     for r in rules:
-        # assign client-side id if missing (not stored)
         if not r.id:
             r.id = str(uuid.uuid4())
 
-        # build match fragments
+    # attempt to replace rules
-        match_frag: List[str] = []
-        if r.match.iif:
-            match_frag += ["iif", f'"{r.match.iif}"']
-        if r.match.oif:
-            match_frag += ["oif", f'"{r.match.oif}"']
-        if r.match.meta_length is not None:
-            match_frag += ["meta", "length", str(r.match.meta_length)]
-        if r.match.ip_proto:
-            match_frag += ["ip", "protocol", str(r.match.ip_proto)]
-        if r.match.tcp_dport:
-            match_frag += ["tcp", "dport", str(r.match.tcp_dport)]
-        if r.match.udp_dport:
-            match_frag += ["udp", "dport", str(r.match.udp_dport)]
-
-        # build action fragment
-        action_frag: List[str] = []
-        a_type = r.action.type or "accept"
-        if a_type == "drop":
-            action_frag = ["drop"]
-        elif a_type == "accept":
-            action_frag = ["accept"]
-        elif a_type == "queue":
-            num = r.action.queue_num if r.action.queue_num is not None else 0
-            action_frag = ["queue", "num", str(num)]
-        elif a_type == "redirect":
-            if r.action.redirect_port is None:
-                raise HTTPException(status_code=400, detail="redirect action requires redirect_port")
-            action_frag = ["redirect", "to", f":{r.action.redirect_port}"]
-        else:
-            raise HTTPException(status_code=400, detail=f"unsupported action type: {a_type}")
-
-        parts = ["add", "rule", r.family, r.table, r.chain] + match_frag + action_frag
-        script_lines.append(" ".join(parts))
-
-    # apply script lines via binding (line-by-line)
-    tmpfile_path: Optional[str] = None
     try:
-        # keep a temp file copy for debugging if desired (optional)
+        add_rules_replace_all(rules, fam, table, chain)
-        with tempfile.NamedTemporaryFile(mode="w", delete=False, prefix="mitm_nft_", suffix=".nft") as tf:
+    except Exception as e:
-            tmpfile_path = tf.name
+        logger.error("failed to apply rules: %s", e)
-            tf.write("\n".join(script_lines) + "\n")
+        raise HTTPException(status_code=500, detail=str(e))
-            tf.flush()
-            os.fsync(tf.fileno())
-        logger.info("wrote nft script to %s; applying line-by-line via binding...", tmpfile_path)
 
-        try:
+    _current_version = str(uuid.uuid4())
-            for ln in script_lines:
+    logger.info("applied nft ruleset successfully; version=%s", _current_version)
-                ln = ln.strip()
+    return ReplaceResult(version=_current_version, applied=True, rules_count=len(rules))
-                if not ln:
-                    continue
-                nft_run_or_raise(ln)
-        except RuntimeError as e:
-            logger.error("failed applying nft script line '%s': %s", ln if 'ln' in locals() else "<unknown>", e)
-            raise HTTPException(status_code=500, detail=f"failed applying nft script: {e}")
-
-        # success -> bump version
-        _current_version = str(uuid.uuid4())
-        logger.info("applied nft ruleset successfully; version=%s", _current_version)
-        return ReplaceResult(version=_current_version, applied=True, rules_count=len(rules))
-    finally:
-        if tmpfile_path and os.path.exists(tmpfile_path):
-            try:
-                os.remove(tmpfile_path)
-            except Exception:
-                logger.debug("failed to remove temp nft script %s", tmpfile_path)