1 .\" $KAME: ipsec_set_policy.3,v 1.16 2003/01/06 21:59:03 sumikawa Exp $
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31 .Dt IPSEC_SET_POLICY 3
34 .Nm ipsec_set_policy ,
35 .Nm ipsec_get_policylen ,
37 .Nd manipulate IPsec policy specification structure from readable string
42 .Fd #include <netinet6/ipsec.h>
44 .Fn ipsec_set_policy "char *policy" "int len"
46 .Fn ipsec_get_policylen "char *buf"
48 .Fn ipsec_dump_policy "char *buf" "char *delim"
51 generates IPsec policy specification structure, namely
52 .Li struct sadb_x_policy
54 .Li struct sadb_x_ipsecrequest
55 from human-readable policy specification.
56 policy specification must be given as C string
63 will return the buffer of IPsec policy specification structure.
64 The buffer is dynamically allocated, and must be freed by the caller by calling
67 You may want the length of the generated buffer such when calling
69 .Fn ipsec_get_policylen
70 will return the length.
73 converts IPsec policy structure into readable form.
76 can be regarded as inverse conversion of
77 .Fn ipsec_set_policy .
79 points to an IPsec policy structure,
80 .Li struct sadb_x_policy .
82 is a delimiter string, which is usually a blank character.
87 single whitespace is assumed.
89 returns pointer to dynamically allocated string.
90 It is caller's responsibility to reclaim the region, by using
94 is formatted as either of the following:
95 .Bl -tag -width "discard"
96 .It Ar direction [priority specification] Li discard
105 specifies which direction the policy needs to be applied. Nonstandard
110 on platforms which do not support forward policies.
112 .Ar priority specification
113 is used to control the placement of the policy within the SPD. Policy position
115 a signed integer where higher priorities indicate the policy is placed
116 closer to the beginning of the list and lower priorities indicate the
117 policy is placed closer to the end of the list. Policies with equal
118 priorities are added at the end of the group of such policies.
121 be specified when libipsec has been compiled against kernel headers that
122 support policy priorities (>= 2.6.6). It takes one of the following formats:
123 .Bl -tag -width "discard"
125 .Ar {priority,prio} offset
128 is an integer in ranges -2147483647 .. 214783648.
130 .Ar {priority,prio} base {+,-} offset
134 .Li low (-1073741824),
137 .Li high (1073741824)
140 is an unsigned integer. It can be up to 1073741824 for
141 positive offsets, and up to 1073741823 for negative offsets.
144 The interpretation of policy priority in these functions and the kernel DOES
145 differ. The relationship between the two can be described as
146 p(kernel) = 0x80000000 - p(func)
150 policy, packets will be dropped if they match the policy.
151 .It Ar direction [priority specification] Li entrust
153 means to consult to SPD defined by
155 .It Ar direction [priority specification] Li bypass
157 means to be bypassed the IPsec processing.
158 .Pq packet will be transmitted in clear .
159 This is for privileged socket.
162 .Ar [priority specification]
167 means that the matching packets are subject to IPsec processing.
169 can be followed by one or more
171 string, which is formatted as below:
172 .Bl -tag -width "discard"
199 specifies IPsec endpoint.
228 must be set to one of the following:
229 .Li default , use , require
233 means that the kernel should consult the system default policy
237 .Li net.inet.ipsec.esp_trans_deflev .
240 regarding the system default.
242 means that a relevant SA can be used when available,
243 since the kernel may perform IPsec operation against packets when possible.
244 In this case, packets can be transmitted in clear
245 .Pq when SA is not available ,
247 .Pq when SA is available .
249 means that a relevant SA is required,
250 since the kernel must perform IPsec operation against packets.
254 but adds the restriction that the SA for outbound traffic is used
255 only for this policy.
256 You may need the identifier in order to relate the policy and the SA
257 when you define the SA by manual keying.
258 You can put the decimal number as the identifier after
261 .Li unique : number .
263 must be between 1 and 32767 .
266 string is kept unambiguous,
271 However, it is encouraged to specify them explicitly
272 to avoid unintended behaviors.
275 is omitted, it will be interpreted as
279 Note that there is a bit difference of specification from
283 both entrust and bypass are not used.
288 Here are several examples
289 .Pq long lines are wrapped for readability :
290 .Bd -literal -offset indent
292 out ipsec esp/transport//require
293 in ipsec ah/transport//require
294 out ipsec esp/tunnel/10.1.1.2-10.1.1.1/use
295 in ipsec ipcomp/transport//use
301 returns a pointer to the allocated buffer of policy specification if successful; otherwise a NULL pointer is returned.
302 .Fn ipsec_get_policylen
303 returns with positive value
304 .Pq meaning the buffer size
305 on success, and negative value on errors.
306 .Fn ipsec_dump_policy
307 returns a pointer to dynamically allocated region on success,
312 .Xr ipsec_strerror 3 ,
316 The functions first appeared in WIDE/KAME IPv6 protocol stack kit.