1 files changed, 325 insertions, 0 deletions
diff --git a/rust/src/sip/parser.rs b/rust/src/sip/parser.rs
new file mode 100644
index 0000000..a34bc26
--- /dev/null
+++ b/rust/src/sip/parser.rs
@@ -0,0 +1,325 @@
+/* Copyright (C) 2019-2022 Open Information Security Foundation
+ *
+ * You can copy, redistribute or modify this Program under the terms of
+ * the GNU General Public License version 2 as published by the Free
+ * Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+// written by Giuseppe Longo <giuseppe@glono.it>
+
+use nom7::bytes::streaming::{take, take_while, take_while1};
+use nom7::character::streaming::{char, crlf};
+use nom7::character::{is_alphabetic, is_alphanumeric, is_space};
+use nom7::combinator::map_res;
+use nom7::sequence::delimited;
+use nom7::{Err, IResult, Needed};
+use std;
+use std::collections::HashMap;
+
+#[derive(Debug)]
+pub struct Header {
+    pub name: String,
+    pub value: String,
+}
+
+#[derive(Debug)]
+pub struct Request {
+    pub method: String,
+    pub path: String,
+    pub version: String,
+    pub headers: HashMap<String, String>,
+
+    pub request_line_len: u16,
+    pub headers_len: u16,
+    pub body_offset: u16,
+    pub body_len: u16,
+}
+
+#[derive(Debug)]
+pub struct Response {
+    pub version: String,
+    pub code: String,
+    pub reason: String,
+
+    pub response_line_len: u16,
+    pub headers_len: u16,
+    pub body_offset: u16,
+    pub body_len: u16,
+}
+
+#[inline]
+fn is_token_char(b: u8) -> bool {
+    is_alphanumeric(b) || b"!%'*+-._`".contains(&b)
+}
+
+#[inline]
+fn is_method_char(b: u8) -> bool {
+    is_alphabetic(b)
+}
+
+#[inline]
+fn is_request_uri_char(b: u8) -> bool {
+    is_alphanumeric(b) || is_token_char(b) || b"~#@:".contains(&b)
+}
+
+#[inline]
+fn is_version_char(b: u8) -> bool {
+    is_alphanumeric(b) || b"./".contains(&b)
+}
+
+#[inline]
+fn is_reason_phrase(b: u8) -> bool {
+    is_alphanumeric(b) || is_token_char(b) || b"$&(),/:;=?@[\\]^ ".contains(&b)
+}
+
+fn is_header_name(b: u8) -> bool {
+    is_alphanumeric(b) || is_token_char(b)
+}
+
+fn is_header_value(b: u8) -> bool {
+    is_alphanumeric(b) || is_token_char(b) || b"\"#$&(),/;:<=>?@[]{}()^|~\\\t\n\r ".contains(&b)
+}
+
+pub fn sip_parse_request(oi: &[u8]) -> IResult<&[u8], Request> {
+    let (i, method) = parse_method(oi)?;
+    let (i, _) = char(' ')(i)?;
+    let (i, path) = parse_request_uri(i)?;
+    let (i, _) = char(' ')(i)?;
+    let (i, version) = parse_version(i)?;
+    let (hi, _) = crlf(i)?;
+    let request_line_len = oi.len() - hi.len();
+    let (phi, headers) = parse_headers(hi)?;
+    let headers_len = hi.len() - phi.len();
+    let (bi, _) = crlf(phi)?;
+    let body_offset = oi.len() - bi.len();
+    Ok((
+        bi,
+        Request {
+            method: method.into(),
+            path: path.into(),
+            version: version.into(),
+            headers,
+
+            request_line_len: request_line_len as u16,
+            headers_len: headers_len as u16,
+            body_offset: body_offset as u16,
+            body_len: bi.len() as u16,
+        },
+    ))
+}
+
+pub fn sip_parse_response(oi: &[u8]) -> IResult<&[u8], Response> {
+    let (i, version) = parse_version(oi)?;
+    let (i, _) = char(' ')(i)?;
+    let (i, code) = parse_code(i)?;
+    let (i, _) = char(' ')(i)?;
+    let (i, reason) = parse_reason(i)?;
+    let (hi, _) = crlf(i)?;
+    let response_line_len = oi.len() - hi.len();
+    let (phi, _headers) = parse_headers(hi)?;
+    let headers_len = hi.len() - phi.len();
+    let (bi, _) = crlf(phi)?;
+    let body_offset = oi.len() - bi.len();
+    Ok((
+        bi,
+        Response {
+            version: version.into(),
+            code: code.into(),
+            reason: reason.into(),
+
+            response_line_len: response_line_len as u16,
+            headers_len: headers_len as u16,
+            body_offset: body_offset as u16,
+            body_len: bi.len() as u16,
+        },
+    ))
+}
+
+#[inline]
+fn parse_method(i: &[u8]) -> IResult<&[u8], &str> {
+    map_res(take_while(is_method_char), std::str::from_utf8)(i)
+}
+
+#[inline]
+fn parse_request_uri(i: &[u8]) -> IResult<&[u8], &str> {
+    map_res(take_while1(is_request_uri_char), std::str::from_utf8)(i)
+}
+
+#[inline]
+fn parse_version(i: &[u8]) -> IResult<&[u8], &str> {
+    map_res(take_while1(is_version_char), std::str::from_utf8)(i)
+}
+
+#[inline]
+fn parse_code(i: &[u8]) -> IResult<&[u8], &str> {
+    map_res(take(3_usize), std::str::from_utf8)(i)
+}
+
+#[inline]
+fn parse_reason(i: &[u8]) -> IResult<&[u8], &str> {
+    map_res(take_while(is_reason_phrase), std::str::from_utf8)(i)
+}
+
+#[inline]
+fn header_name(i: &[u8]) -> IResult<&[u8], &str> {
+    map_res(take_while(is_header_name), std::str::from_utf8)(i)
+}
+
+#[inline]
+fn header_value(i: &[u8]) -> IResult<&[u8], &str> {
+    map_res(parse_header_value, std::str::from_utf8)(i)
+}
+
+#[inline]
+fn hcolon(i: &[u8]) -> IResult<&[u8], char> {
+    delimited(take_while(is_space), char(':'), take_while(is_space))(i)
+}
+
+fn message_header(i: &[u8]) -> IResult<&[u8], Header> {
+    let (i, n) = header_name(i)?;
+    let (i, _) = hcolon(i)?;
+    let (i, v) = header_value(i)?;
+    let (i, _) = crlf(i)?;
+    Ok((
+        i,
+        Header {
+            name: String::from(n),
+            value: String::from(v),
+        },
+    ))
+}
+
+pub fn sip_take_line(i: &[u8]) -> IResult<&[u8], Option<String>> {
+    let (i, line) = map_res(take_while1(is_reason_phrase), std::str::from_utf8)(i)?;
+    Ok((i, Some(line.into())))
+}
+
+pub fn parse_headers(mut input: &[u8]) -> IResult<&[u8], HashMap<String, String>> {
+    let mut headers_map: HashMap<String, String> = HashMap::new();
+    loop {
+        match crlf(input) as IResult<&[u8], _> {
+            Ok((_, _)) => {
+                break;
+            }
+            Err(Err::Error(_)) => {}
+            Err(Err::Failure(_)) => {}
+            Err(Err::Incomplete(e)) => return Err(Err::Incomplete(e)),
+        };
+        let (rest, header) = message_header(input)?;
+        headers_map.insert(header.name, header.value);
+        input = rest;
+    }
+
+    Ok((input, headers_map))
+}
+
+fn parse_header_value(buf: &[u8]) -> IResult<&[u8], &[u8]> {
+    let mut end_pos = 0;
+    let mut trail_spaces = 0;
+    let mut idx = 0;
+    while idx < buf.len() {
+        match buf[idx] {
+            b'\n' => {
+                idx += 1;
+                if idx >= buf.len() {
+                    return Err(Err::Incomplete(Needed::new(1)));
+                }
+                match buf[idx] {
+                    b' ' | b'\t' => {
+                        idx += 1;
+                        continue;
+                    }
+                    _ => {
+                        return Ok((&buf[(end_pos + trail_spaces)..], &buf[..end_pos]));
+                    }
+                }
+            }
+            b' ' | b'\t' => {
+                trail_spaces += 1;
+            }
+            b'\r' => {}
+            b => {
+                trail_spaces = 0;
+                if !is_header_value(b) {
+                    return Err(Err::Incomplete(Needed::new(1)));
+                }
+                end_pos = idx + 1;
+            }
+        }
+        idx += 1;
+    }
+    Ok((&b""[..], buf))
+}
+
+#[cfg(test)]
+mod tests {
+
+    use crate::sip::parser::*;
+
+    #[test]
+    fn test_parse_request() {
+        let buf: &[u8] = "REGISTER sip:sip.cybercity.dk SIP/2.0\r\n\
+                          From: <sip:voi18063@sip.cybercity.dk>;tag=903df0a\r\n\
+                          To: <sip:voi18063@sip.cybercity.dk>\r\n\
+                          Content-Length: 0\r\n\
+                          \r\n"
+            .as_bytes();
+
+        match sip_parse_request(buf) {
+            Ok((_, req)) => {
+                assert_eq!(req.method, "REGISTER");
+                assert_eq!(req.path, "sip:sip.cybercity.dk");
+                assert_eq!(req.version, "SIP/2.0");
+                assert_eq!(req.headers["Content-Length"], "0");
+            }
+            _ => {
+                assert!(false);
+            }
+        }
+    }
+
+    #[test]
+    fn test_parse_request_trail_space_header() {
+        let buf: &[u8] = "REGISTER sip:sip.cybercity.dk SIP/2.0\r\n\
+                          From: <sip:voi18063@sip.cybercity.dk>;tag=903df0a\r\n\
+                          To: <sip:voi18063@sip.cybercity.dk>\r\n\
+                          Content-Length: 4  \r\n\
+                          \r\nABCD"
+            .as_bytes();
+
+        let (body, req) = sip_parse_request(buf).expect("parsing failed");
+        assert_eq!(req.method, "REGISTER");
+        assert_eq!(req.path, "sip:sip.cybercity.dk");
+        assert_eq!(req.version, "SIP/2.0");
+        assert_eq!(req.headers["Content-Length"], "4");
+        assert_eq!(body, "ABCD".as_bytes());
+    }
+
+    #[test]
+    fn test_parse_response() {
+        let buf: &[u8] = "SIP/2.0 401 Unauthorized\r\n\
+                          \r\n"
+            .as_bytes();
+
+        match sip_parse_response(buf) {
+            Ok((_, resp)) => {
+                assert_eq!(resp.version, "SIP/2.0");
+                assert_eq!(resp.code, "401");
+                assert_eq!(resp.reason, "Unauthorized");
+            }
+            _ => {
+                assert!(false);
+            }
+        }
+    }
+}