70 lines
2.1 KiB
Plaintext
70 lines
2.1 KiB
Plaintext
#
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# For a description of the syntax of this configuration file,
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# see the file kconfig-language.txt in the NuttX tools repository.
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#
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config NET_NAT
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bool "Network Address Translation (NAT)"
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default n
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depends on NET_IPFORWARD && IOB_BUFSIZE >= 68
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---help---
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Enable or disable Network Address Translation (NAT) function.
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Note: When forwarding IPv4 packet and applying NAT, NAT may be
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applied directly on a single I/O buffer containing L3 packet header,
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and NAT may need a continuous buffer of at least 68 Bytes
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(IPv4 20B + ICMP 8B + IPv4 20B + TCP 20B).
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config NET_NAT_HASH_BITS
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int "The bits of NAT entry hashtable"
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default 5
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range 1 10
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depends on NET_NAT
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---help---
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The hashtable of NAT entries will have (1 << bits) buckets.
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config NET_NAT_TCP_EXPIRE_SEC
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int "TCP NAT entry expiration seconds"
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default 86400
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depends on NET_NAT
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---help---
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The expiration time for idle TCP entry in NAT.
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Note: The default value 86400 is suggested by RFC2663, Section 2.6,
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Page 5.
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config NET_NAT_UDP_EXPIRE_SEC
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int "UDP NAT entry expiration seconds"
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default 240
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depends on NET_NAT
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---help---
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The expiration time for idle UDP entry in NAT.
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Note: RFC2663 (Section 2.6, Page 5) suggests that non-TCP sessions
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that have not been used for a couple of minutes can be assumed to be
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terminated.
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config NET_NAT_ICMP_EXPIRE_SEC
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int "ICMP NAT entry expiration seconds"
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default 60
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depends on NET_NAT
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---help---
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The expiration time for idle ICMP entry in NAT.
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Note: The default value 60 is suggested by RFC5508, Section 3.2,
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Page 8.
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config NET_NAT_ENTRY_RECLAIM_SEC
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int "The time to auto reclaim all expired entries"
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default 3600
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depends on NET_NAT
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---help---
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The time to auto reclaim all expired entries. A value of zero will
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disable auto reclaiming.
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Note: Expired entries will be automatically reclaimed when matching
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inbound/outbound entries, so this config does not have significant
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impact when NAT is normally used, but very useful when the hashtable
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is big and there are only a few connections using NAT (which will
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only trigger reclaiming on a few chains in hashtable).
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