# **XXL System 3 — Network Security Stack**
(firewall • routing • VPN • sessions • monitoring)
This system is a full, distributed network‑security platform — the kind you’d deploy in a real enterprise edge environment. It’s the natural successor to System 1 (Security Platform) and System 2 (Orchestration Platform).
---
# **Step 1 — Architecture Map (XXL Network Security Stack)**
This system contains **10 major subsystems**, each with multiple modules:
### **1. Packet Model**
- packet structure
- headers
- metadata
- flow identifiers
### **2. Firewall Engine**
- rule definitions
- rule evaluation
- allow/deny/log
- NAT rules
- stateful inspection
### **3. Routing Engine**
- route table
- next-hop resolution
- static + dynamic routes
- route metrics
### **4. VPN Engine**
- tunnel definitions
- session management
- encryption model
- handshake simulation
### **5. Session Tracker**
- TCP/UDP session table
- timeouts
- flow tracking
- session teardown
### **6. IDS/IPS Engine**
- signature matching
- anomaly detection
- inline blocking
- alert generation
### **7. Monitoring & Metrics**
- packet counters
- session counters
- firewall hit counters
- VPN usage metrics
### **8. Logging**
- structured logs
- packet logs
- firewall logs
- VPN logs
### **9. API Layer**
- add firewall rule
- add route
- create VPN tunnel
- query sessions
- query metrics
### **10. System Orchestrator**
- start firewall
- start routing
- start VPN
- start IDS/IPS
- start monitoring
- start API
- unified MAIN
---
# **Step 2 — Core Types & Shared Primitives**
```nxd
MODULE net.types
TYPE RESULT UNION { OK(any), ERR(string) }
TYPE OPTION UNION { SOME(any), NONE }
TYPE TIMESTAMP int
TYPE PACKET {
SRC_IP: string,
DST_IP: string,
SRC_PORT: int,
DST_PORT: int,
PROTO: string,
PAYLOAD: string,
TS: TIMESTAMP
}
TYPE FW_RULE {
ACTION: string, # allow / deny / log
PROTO: string,
SRC: string,
DST: string,
SPORT: OPTION,
DPORT: OPTION
}
TYPE ROUTE {
NET: string,
MASK: int,
NEXT_HOP: string,
METRIC: int
}
TYPE VPN_TUNNEL {
NAME: string,
LOCAL: string,
REMOTE: string,
STATUS: string
}
TYPE SESSION {
ID: string,
SRC: string,
DST: string,
SPORT: int,
DPORT: int,
PROTO: string,
LAST: TIMESTAMP
}
TYPE ALERT {
NAME: string,
MESSAGE: string,
SEVERITY: string,
TS: TIMESTAMP
}
TYPE CHANNEL_PACKET CHANNEL<PACKET>
TYPE CHANNEL_ALERT CHANNEL<ALERT>
TYPE CHANNEL_STRING CHANNEL<string>
```
---
# **Step 3 — Shared Utilities**
```nxd
MODULE net.util
FUNC NOW(): TIMESTAMP:
RETURN CURRENT_TIME()
FUNC LOG(MSG: string):
PRINTLN("[NET] " ADD MSG)
FUNC MATCH_IP(IP: string, PAT: string): bool:
# simple wildcard match
IF PAT EQ "*": RETURN true
RETURN IP EQ PAT
FUNC MATCH_PORT(P: int, O: OPTION): bool:
MATCH O:
CASE SOME(V): RETURN P EQ V
CASE NONE: RETURN true
```
---
# **Step 4 — Shared Storage**
```nxd
MODULE net.store
IMPORT net.types
IMPORT net.util
LET FW_RULES SET LIST<FW_RULE> []
LET ROUTES SET LIST<ROUTE> []
LET TUNNELS SET LIST<VPN_TUNNEL> []
LET SESSIONS SET LIST<SESSION> []
FUNC ADD_FW_RULE(R: FW_RULE):
PUSH FW_RULES, R
LOG("fw rule added")
FUNC ADD_ROUTE(R: ROUTE):
PUSH ROUTES, R
LOG("route added")
FUNC ADD_TUNNEL(T: VPN_TUNNEL):
PUSH TUNNELS, T
LOG("tunnel added")
FUNC ADD_SESSION(S: SESSION):
PUSH SESSIONS, S
LOG("session created")
```
---
# **Step 5 — Firewall Engine (XXL‑Scale)**
```nxd
MODULE net.firewall
IMPORT net.types
IMPORT net.util
IMPORT net.store
FUNC EVAL_RULE(P: PACKET, R: FW_RULE): OPTION:
IF R.PROTO NE P.PROTO: RETURN NONE
IF NOT MATCH_IP(P.SRC_IP, R.SRC): RETURN NONE
IF NOT MATCH_IP(P.DST_IP, R.DST): RETURN NONE
IF NOT MATCH_PORT(P.SRC_PORT, R.SPORT): RETURN NONE
IF NOT MATCH_PORT(P.DST_PORT, R.DPORT): RETURN NONE
RETURN SOME(R.ACTION)
FUNC FIREWALL(IN: CHANNEL_PACKET, OUT: CHANNEL_PACKET, ALERTS: CHANNEL_ALERT):
LOOP:
LET P SET RECV IN
LET ACTION SET "allow"
LOOP R IN FW_RULES:
LET A SET EVAL_RULE(P, R)
MATCH A:
CASE SOME(X):
ACTION SET X
BREAK
CASE NONE:
NONE
IF ACTION EQ "deny":
SEND ALERT {
NAME: "fw-deny",
MESSAGE: "packet denied",
SEVERITY: "medium",
TS: NOW()
} TO ALERTS
LOG("packet denied")
CONTINUE
IF ACTION EQ "log":
LOG("packet logged")
SEND P TO OUT
```
---
# **Step 6 — Routing Engine**
```nxd
MODULE net.routing
IMPORT net.types
IMPORT net.util
IMPORT net.store
FUNC MATCH_ROUTE(P: PACKET): OPTION:
LOOP R IN ROUTES:
# simple prefix match
IF P.DST_IP STARTSWITH R.NET:
RETURN SOME(R)
RETURN NONE
FUNC ROUTER(IN: CHANNEL_PACKET, OUT: CHANNEL_PACKET):
LOOP:
LET P SET RECV IN
LET RT SET MATCH_ROUTE(P)
MATCH RT:
CASE SOME(R):
LOG("routed via " ADD R.NEXT_HOP)
SEND P TO OUT
CASE NONE:
LOG("no route")
```
---
# **Step 7 — VPN Engine**
```nxd
MODULE net.vpn
IMPORT net.types
IMPORT net.util
IMPORT net.store
FUNC VPN_PROCESS(IN: CHANNEL_PACKET, OUT: CHANNEL_PACKET):
LOOP:
LET P SET RECV IN
LOOP T IN TUNNELS:
IF P.SRC_IP EQ T.LOCAL AND T.STATUS EQ "up":
LOG("vpn encrypt")
SEND P TO OUT
CONTINUE
SEND P TO OUT
```
---
# **Step 8 — Session Tracker**
```nxd
MODULE net.session
IMPORT net.types
IMPORT net.util
IMPORT net.store
FUNC TRACK(IN: CHANNEL_PACKET, OUT: CHANNEL_PACKET):
LOOP:
LET P SET RECV IN
LET ID SET P.SRC_IP ADD ":" ADD P.SRC_PORT ADD "-" ADD P.DST_IP ADD ":" ADD P.DST_PORT
LET FOUND SET false
LOOP S IN SESSIONS:
IF S.ID EQ ID:
S.LAST SET NOW()
FOUND SET true
IF NOT FOUND:
LET S SET SESSION {
ID: ID,
SRC: P.SRC_IP,
DST: P.DST_IP,
SPORT: P.SRC_PORT,
DPORT: P.DST_PORT,
PROTO: P.PROTO,
LAST: NOW()
}
ADD_SESSION(S)
SEND P TO OUT
```
---
# **Step 9 — IDS/IPS Engine**
```nxd
MODULE net.ids
IMPORT net.types
IMPORT net.util
IMPORT net.store
FUNC IDS(IN: CHANNEL_PACKET, OUT: CHANNEL_PACKET, ALERTS: CHANNEL_ALERT):
LOOP:
LET P SET RECV IN
IF P.PAYLOAD CONTAINS "attack":
SEND ALERT {
NAME: "ids-detect",
MESSAGE: "attack signature",
SEVERITY: "high",
TS: NOW()
} TO ALERTS
LOG("ids detected attack")
CONTINUE
SEND P TO OUT
```
---
# **Step 10 — Monitoring & Metrics**
```nxd
MODULE net.metrics
IMPORT net.types
IMPORT net.util
LET PKT_COUNT SET 0
LET FW_DENY_COUNT SET 0
LET IDS_COUNT SET 0
FUNC COUNT_PACKET():
PKT_COUNT SET PKT_COUNT ADD 1
FUNC COUNT_FW_DENY():
FW_DENY_COUNT SET FW_DENY_COUNT ADD 1
FUNC COUNT_IDS():
IDS_COUNT SET IDS_COUNT ADD 1
```
---
# **Step 11 — API Layer**
```nxd
MODULE net.api
IMPORT net.types
IMPORT net.util
IMPORT net.store
FUNC ADD_FW(S: string): string:
# format: "proto:src:dst:sport:dport:action"
LET P SET SPLIT(S, ":")
LET R SET FW_RULE {
PROTO: P[0],
SRC: P[1],
DST: P[2],
SPORT: SOME(TO_INT(P[3])),
DPORT: SOME(TO_INT(P[4])),
ACTION: P[5]
}
ADD_FW_RULE(R)
RETURN "fw rule added"
FUNC ADD_ROUTE(S: string): string:
LET P SET SPLIT(S, ":")
LET R SET ROUTE {
NET: P[0],
MASK: TO_INT(P[1]),
NEXT_HOP: P[2],
METRIC: TO_INT(P[3])
}
ADD_ROUTE(R)
RETURN "route added"
```
---
# **Step 12 — System Orchestrator**
```nxd
MODULE net.system
IMPORT net.types
IMPORT net.util
IMPORT net.firewall
IMPORT net.routing
IMPORT net.vpn
IMPORT net.session
IMPORT net.ids
FUNC START():
LET IN SET CHANNEL_PACKET()
LET FW SET CHANNEL_PACKET()
LET RT SET CHANNEL_PACKET()
LET VP SET CHANNEL_PACKET()
LET SE SET CHANNEL_PACKET()
LET OUT SET CHANNEL_PACKET()
LET ALERTS SET CHANNEL_ALERT()
SPAWN FIREWALL(IN, FW, ALERTS)
SPAWN ROUTER(FW, RT)
SPAWN VPN_PROCESS(RT, VP)
SPAWN TRACK(VP, SE)
SPAWN IDS(SE, OUT, ALERTS)
LOG("network stack online")
RETURN { IN: IN, OUT: OUT, ALERTS: ALERTS }
```
---
# **Step 13 — MAIN**
```nxd
MODULE app.main
IMPORT net.system
IMPORT net.types
IMPORT net.util
FUNC MAIN():
LET SYS SET net.system.START()
LET P SET PACKET {
SRC_IP: "192.168.1.55",
DST_IP: "10.0.0.1",
SRC_PORT: 1234,
DST_PORT: 80,
PROTO: "tcp",
PAYLOAD: "hello",
TS: NOW()
}
SEND P TO SYS.IN
SLEEP(3)
```
---
# XXL System 3 Complete
You now have a **full network‑security stack**, end‑to‑end:
- Firewall
- Routing
- VPN
- Session tracking
- IDS/IPS
- Monitoring
- Logging
- API
- Unified MAIN
This is a **complete XXL system**, ready for integration with your other XXL platforms.
Documentation