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author | Kenny Root <kenny@the-b.org> | 2015-07-18 11:30:18 -0700 |
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committer | Kenny Root <kenny@the-b.org> | 2015-07-18 11:30:18 -0700 |
commit | 2f5f3754dce85212a71138fd80c2300b73461908 (patch) | |
tree | ac51a1c9f143bc77a0cfec2e7da1b7c184394a98 /sshlib/src/main/java/com/trilead/ssh2/DHGexParameters.java | |
parent | 0cf7ac30faecc82e04b080f418b08758624b07f5 (diff) | |
download | sshlib-2f5f3754dce85212a71138fd80c2300b73461908.tar.gz sshlib-2f5f3754dce85212a71138fd80c2300b73461908.tar.bz2 sshlib-2f5f3754dce85212a71138fd80c2300b73461908.zip |
Rename project to sshlib
Diffstat (limited to 'sshlib/src/main/java/com/trilead/ssh2/DHGexParameters.java')
-rw-r--r-- | sshlib/src/main/java/com/trilead/ssh2/DHGexParameters.java | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/sshlib/src/main/java/com/trilead/ssh2/DHGexParameters.java b/sshlib/src/main/java/com/trilead/ssh2/DHGexParameters.java new file mode 100644 index 0000000..7872358 --- /dev/null +++ b/sshlib/src/main/java/com/trilead/ssh2/DHGexParameters.java @@ -0,0 +1,121 @@ + +package com.trilead.ssh2; + +/** + * A <code>DHGexParameters</code> object can be used to specify parameters for + * the diffie-hellman group exchange. + * <p> + * Depending on which constructor is used, either the use of a + * <code>SSH_MSG_KEX_DH_GEX_REQUEST</code> or <code>SSH_MSG_KEX_DH_GEX_REQUEST_OLD</code> + * can be forced. + * + * @see Connection#setDHGexParameters(DHGexParameters) + * @author Christian Plattner, plattner@trilead.com + * @version $Id: DHGexParameters.java,v 1.1 2007/10/15 12:49:56 cplattne Exp $ + */ + +public class DHGexParameters +{ + private final int min_group_len; + private final int pref_group_len; + private final int max_group_len; + + private static final int MIN_ALLOWED = 1024; + private static final int MAX_ALLOWED = 8192; + + /** + * Same as calling {@link #DHGexParameters(int, int, int) DHGexParameters(1024, 1024, 4096)}. + * This is also the default used by the Connection class. + * + */ + public DHGexParameters() + { + this(1024, 1024, 4096); + } + + /** + * This constructor can be used to force the sending of a + * <code>SSH_MSG_KEX_DH_GEX_REQUEST_OLD</code> request. + * Internally, the minimum and maximum group lengths will + * be set to zero. + * + * @param pref_group_len has to be >= 1024 and <= 8192 + */ + public DHGexParameters(int pref_group_len) + { + if ((pref_group_len < MIN_ALLOWED) || (pref_group_len > MAX_ALLOWED)) + throw new IllegalArgumentException("pref_group_len out of range!"); + + this.pref_group_len = pref_group_len; + this.min_group_len = 0; + this.max_group_len = 0; + } + + /** + * This constructor can be used to force the sending of a + * <code>SSH_MSG_KEX_DH_GEX_REQUEST</code> request. + * <p> + * Note: older OpenSSH servers don't understand this request, in which + * case you should use the {@link #DHGexParameters(int)} constructor. + * <p> + * All values have to be >= 1024 and <= 8192. Furthermore, + * min_group_len <= pref_group_len <= max_group_len. + * + * @param min_group_len + * @param pref_group_len + * @param max_group_len + */ + public DHGexParameters(int min_group_len, int pref_group_len, int max_group_len) + { + if ((min_group_len < MIN_ALLOWED) || (min_group_len > MAX_ALLOWED)) + throw new IllegalArgumentException("min_group_len out of range!"); + + if ((pref_group_len < MIN_ALLOWED) || (pref_group_len > MAX_ALLOWED)) + throw new IllegalArgumentException("pref_group_len out of range!"); + + if ((max_group_len < MIN_ALLOWED) || (max_group_len > MAX_ALLOWED)) + throw new IllegalArgumentException("max_group_len out of range!"); + + if ((pref_group_len < min_group_len) || (pref_group_len > max_group_len)) + throw new IllegalArgumentException("pref_group_len is incompatible with min and max!"); + + if (max_group_len < min_group_len) + throw new IllegalArgumentException("max_group_len must not be smaller than min_group_len!"); + + this.min_group_len = min_group_len; + this.pref_group_len = pref_group_len; + this.max_group_len = max_group_len; + } + + /** + * Get the maximum group length. + * + * @return the maximum group length, may be <code>zero</code> if + * SSH_MSG_KEX_DH_GEX_REQUEST_OLD should be requested + */ + public int getMax_group_len() + { + return max_group_len; + } + + /** + * Get the minimum group length. + * + * @return minimum group length, may be <code>zero</code> if + * SSH_MSG_KEX_DH_GEX_REQUEST_OLD should be requested + */ + public int getMin_group_len() + { + return min_group_len; + } + + /** + * Get the preferred group length. + * + * @return the preferred group length + */ + public int getPref_group_len() + { + return pref_group_len; + } +} |