Mercurial > dropbear
comparison SMALL @ 4:fe6bca95afa7
Makefile.in contains updated files required
| author | Matt Johnston <matt@ucc.asn.au> |
|---|---|
| date | Tue, 01 Jun 2004 02:46:09 +0000 |
| parents | |
| children | b9d3f725e00b |
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| 1 Tips for a small system: | |
| 2 | |
| 3 The following are set in options.h | |
| 4 | |
| 5 - You can safely disable blowfish and twofish ciphers, and MD5 hmac, without | |
| 6 affecting interoperability | |
| 7 | |
| 8 - If you're compiling statically, you can turn off host lookups | |
| 9 | |
| 10 - You can disable either password or public-key authentication, though note | |
| 11 that the IETF draft states that pubkey authentication is required. | |
| 12 | |
| 13 - Similarly with DSS and RSA, you can disable one of these if you know that | |
| 14 all clients will be able to support a particular one. The IETF draft | |
| 15 states that DSS is required, however you may prefer to use RSA. | |
| 16 DON'T disable either of these on systems where you aren't 100% sure about | |
| 17 who will be connecting and what clients they will be using. | |
| 18 | |
| 19 - Disabling the MOTD code and SFTP-SERVER may save a small amount of codesize | |
| 20 | |
| 21 - You can disable x11, tcp and agent forwarding as desired. None of these are | |
| 22 essential, although agent-forwarding is often useful even on firewall boxes. | |
| 23 | |
| 24 If you are compiling statically, you may want to disable zlib, as it will use | |
| 25 a few tens of kB of binary-size (./configure --disable-zlib). | |
| 26 | |
| 27 You can create a combined binary, see the file MULTI, which will put all | |
| 28 the functions into one binary, avoiding repeated code. | |
| 29 | |
| 30 If you're compiling with gcc, you might want to look at gcc's options for | |
| 31 stripping unused code. The relevant vars to set before configure are: | |
| 32 | |
| 33 LDFLAGS=-Wl,--gc-sections | |
| 34 CFLAGS="-ffunction-sections -fdata-sections" | |
| 35 | |
| 36 You can also experiment with optimisation flags such as -Os, note that in some | |
| 37 cases these flags actually seem to increase size, so experiment before | |
| 38 deciding. | |
| 39 | |
| 40 Of course using small C libraries such as uClibc and dietlibc can also help. | |
| 41 | |
| 42 If you have any queries, mail me and I'll see if I can help. |