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wireforge_app/ssh/
banner.rs

1//! SSH banner line parser (RFC 4253 ยง4.2).
2
3use std::str;
4
5pub struct SshBanner<'a> { buf: &'a [u8], proto_end: usize, sw_end: usize }
6
7impl<'a> SshBanner<'a> {
8    pub fn parse(buf: &'a [u8]) -> Option<Self> {
9        let text = str::from_utf8(buf).ok()?;
10        if !text.starts_with("SSH-") { return None; }
11        let line = if let Some(pos) = text.find("\r\n") { &text[..pos] } else { text };
12        let proto = &line[4..]; // after "SSH-"
13        let dash = proto.find('-')?;
14        let proto_end = 4 + dash;
15        let sw_end = line.len();
16        Some(Self { buf, proto_end, sw_end })
17    }
18
19    pub fn protocol_version(&self) -> &str {
20        str::from_utf8(&self.buf[4..self.proto_end]).unwrap_or("")
21    }
22
23    pub fn software(&self) -> &str {
24        str::from_utf8(&self.buf[self.proto_end + 1..self.sw_end]).unwrap_or("")
25    }
26
27    pub fn raw(&self) -> &str {
28        str::from_utf8(&self.buf[..self.sw_end]).unwrap_or("")
29    }
30}
31
32#[cfg(test)]
33mod tests {
34    use super::*;
35
36    #[test]
37    fn parse_openssh_banner() {
38        let data = b"SSH-2.0-OpenSSH_8.9\r\n";
39        let b = SshBanner::parse(data).unwrap();
40        assert_eq!(b.protocol_version(), "2.0");
41        assert_eq!(b.software(), "OpenSSH_8.9");
42    }
43
44    #[test]
45    fn parse_dropbear_banner() {
46        let data = b"SSH-2.0-dropbear_2022.83\r\n";
47        let b = SshBanner::parse(data).unwrap();
48        assert_eq!(b.software(), "dropbear_2022.83");
49    }
50
51    #[test]
52    fn parse_not_ssh() {
53        assert!(SshBanner::parse(b"GET / HTTP/1.1\r\n").is_none());
54    }
55}