Module: sip-router Branch: andrei/raw_sock Commit: 869a731313e489254fb220ce52120b7682a2526c URL: http://git.sip-router.org/cgi-bin/gitweb.cgi/sip-router/?a=commit;h=869a7313...
Author: Andrei Pelinescu-Onciul andrei@iptel.org Committer: Andrei Pelinescu-Onciul andrei@iptel.org Date: Tue Jun 15 16:27:55 2010 +0200
raw sockets: build ip header & fragmentation support
Support for sending on raw sockets with IP_HDRINCL or IPPROTO_RAW, that require building the IP header and fragmentation.
---
raw_sock.c | 165 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++-- raw_sock.h | 6 ++- 2 files changed, 164 insertions(+), 7 deletions(-)
diff --git a/raw_sock.c b/raw_sock.c index e8b90b1..136f595 100644 --- a/raw_sock.c +++ b/raw_sock.c @@ -24,11 +24,12 @@ * History: * -------- * 2010-06-07 initial version (from older code) andrei + * 2010-06-15 IP_HDRINCL raw socket support, including on-send + * fragmentation (andrei) */ /* * FIXME: IP_PKTINFO & IP_HDRINCL - linux specific * FIXME: linux specific iphdr and udphdr - * FIXME: send support for IP_HDRINCL */
#ifdef USE_RAW_SOCKS @@ -37,7 +38,8 @@ #include "ip_addr.h" #include "dprint.h" #include "str.h" -#include "ut.h" +#include "rand/fastrand.h" +#include "globals.h"
#include <errno.h> #include <string.h> @@ -99,7 +101,7 @@ int raw_socket(int proto, struct ip_addr* ip, str* iface, int iphdr_incl) } t=IP_PMTUDISC_DONT; if(setsockopt(sock, IPPROTO_IP, IP_MTU_DISCOVER, &t, sizeof(t)) ==-1){ - LOG(L_ERR, "raw_socket: setsockopt(IP_MTU_DISCOVER): %s\n", + ERR("raw_socket: setsockopt(IP_MTU_DISCOVER): %s\n", strerror(errno)); goto error; } @@ -275,7 +277,7 @@ int raw_udp4_recv(int rsock, char** buf, int len, union sockaddr_union* from, n=-3; goto error; }else{ - LOG(L_ERR, "udp length too small: %d/%d\n", + ERR("udp length too small: %d/%d\n", (int)udp_len, (int)(end-udph_start)); n=-3; goto error; @@ -290,7 +292,7 @@ int raw_udp4_recv(int rsock, char** buf, int len, union sockaddr_union* from, dst_ip.u.addr32[0]=iph.daddr; /* fill dst_port */ dst_port=ntohs(udph.dest); - ip_addr2su(to, &dst_ip, port); + ip_addr2su(to, &dst_ip, dst_port); /* fill src_port */ src_port=ntohs(udph.source); su_setport(from, src_port); @@ -403,6 +405,34 @@ inline static int mk_udp_hdr(struct udphdr* u, struct sockaddr_in* from,
+/** fill in an ip header. + * Note: the checksum is _not_ computed + * @param iph - ip header that will be filled. + * @param from - source ip v4 address (network byte order). + * @param to - destination ip v4 address (network byte order). + * @param payload len - payload length (not including the ip header). + * @param proto - protocol. + * @return 0 on success, < 0 on error. + */ +inline static int mk_ip_hdr(struct iphdr* iph, struct in_addr* from, + struct in_addr* to, int payload_len, unsigned char proto) +{ + iph->ihl = sizeof(struct iphdr)/4; + iph->version = 4; + iph->tos = tos; + iph->tot_len = htons(payload_len); + iph->id = 0; + iph->frag_off = 0; /* first 3 bits = flags = 0, last 13 bits = offset */ + iph->ttl = 63; /* FIXME: use some configured value */ + iph->protocol = proto; + iph->check = 0; + iph->saddr = from->s_addr; + iph->daddr = to->s_addr; + return 0; +} + + + /** send an udp packet over a raw socket. * @param rsock - raw socket * @param buf - data @@ -413,7 +443,8 @@ inline static int mk_udp_hdr(struct udphdr* u, struct sockaddr_in* from, * @return <0 on error (errno set too), number of bytes sent on success * (including the udp header => on success len + udpheader size). */ -int raw_udp4_send(int rsock, char* buf, int len, union sockaddr_union* from, +int raw_udp4_send(int rsock, char* buf, unsigned int len, + union sockaddr_union* from, union sockaddr_union* to) { struct msghdr snd_msg; @@ -453,4 +484,126 @@ int raw_udp4_send(int rsock, char* buf, int len, union sockaddr_union* from,
+/** send an udp packet over an IP_HDRINCL raw socket. + * If needed, send several fragments. + * @param rsock - raw socket + * @param buf - data + * @param len - data len + * @param from - source address:port (_must_ be non-null, but the ip address + * can be 0, in which case it will be filled by the kernel). + * @param to - destination address:port + * @param mtu - maximum datagram size (including the ip header, excluding + * link layer headers). Minimum allowed size is 28 + * (sizeof(ip_header + udp_header)). If mtu is lower, it will + * be ignored (the packet will be sent un-fragmented). + * 0 can be used to disable fragmentation. + * @return <0 on error (-2: datagram too big, -1: check errno), + * number of bytes sent on success + * (including the ip & udp headers => + * on success len + udpheader + ipheader size). + */ +int raw_iphdr_udp4_send(int rsock, char* buf, unsigned int len, + union sockaddr_union* from, + union sockaddr_union* to, unsigned short mtu) +{ + struct msghdr snd_msg; + struct iovec iov[2]; + struct ip_udp_hdr { + struct iphdr ip; + struct udphdr udp; + } hdr; + unsigned int totlen; + unsigned int ip_frag_size; /* fragment size */ + unsigned int last_frag_extra; /* extra bytes possible in the last frag */ + unsigned int ip_payload; + unsigned int last_frag_offs; + void* last_frag_start; + int frg_no; + int ret; + + totlen = len + sizeof(hdr); + if (unlikely(totlen) > 65535) + return -2; + memset(&snd_msg, 0, sizeof(snd_msg)); + snd_msg.msg_name=&to->sin; + snd_msg.msg_namelen=sockaddru_len(*to); + snd_msg.msg_iov=&iov[0]; + /* prepare the udp & ip headers */ + mk_udp_hdr(&hdr.udp, &from->sin, &to->sin, (unsigned char*)buf, len, 1); + mk_ip_hdr(&hdr.ip, &from->sin.sin_addr, &to->sin.sin_addr, + len + sizeof(hdr.udp), IPPROTO_UDP); + iov[0].iov_base=(char*)&hdr; + iov[0].iov_len=sizeof(hdr); + snd_msg.msg_iovlen=2; + snd_msg.msg_control=0; + snd_msg.msg_controllen=0; + snd_msg.msg_flags=0; + /* this part changes for different fragments */ + /* packets are fragmented if mtu has a valid value (at least an + IP header + UDP header fit in it) and if the total length is greater + then the mtu */ + if (likely(totlen <= mtu || mtu <= sizeof(hdr))) { + iov[1].iov_base=buf; + iov[1].iov_len=len; + ret=sendmsg(rsock, &snd_msg, 0); + } else { + ip_payload = len + sizeof(hdr.udp); + /* a fragment offset must be a multiple of 8 => its size must + also be a multiple of 8, except for the last fragment */ + ip_frag_size = (mtu -sizeof(hdr.ip)) & (~7); + last_frag_extra = (mtu - sizeof(hdr.ip)) & 7; /* rest */ + frg_no = ip_payload / ip_frag_size + + ((ip_payload % ip_frag_size) > last_frag_extra); + /*ip_last_frag_size = ip_payload % frag_size + + ((ip_payload % frag_size) <= last_frag_extra) * + ip_frag_size; */ + last_frag_offs = (frg_no - 1) * ip_frag_size; + /* if we are here mtu => sizeof(ip_h+udp_h) && payload > mtu + => last_frag_offs >= sizeof(hdr.udp) */ + last_frag_start = buf + last_frag_offs - sizeof(hdr.udp); + hdr.ip.id = fastrand_max(65534) + 1; /* random id, should be != 0 + (if 0 the kernel will fill it) */ + /* send the first fragment */ + iov[1].iov_base=buf; + /* ip_frag_size >= sizeof(hdr.udp) because we are here only + if mtu >= sizeof(hdr.ip) + sizeof(hdr.udp) */ + iov[1].iov_len=ip_frag_size - sizeof(hdr.udp); + hdr.ip.tot_len = htons(ip_frag_size); + hdr.ip.frag_off = htons(0x2000); /* set MF */ + ret=sendmsg(rsock, &snd_msg, 0); + if (unlikely(ret < 0)) + goto end; + /* all the other fragments, include only the ip header */ + iov[0].iov_len = sizeof(hdr.ip); + iov[1].iov_base = (char*)iov[1].iov_base + iov[1].iov_len; + /* fragments between the first and the last */ + while(unlikely(iov[1].iov_base < last_frag_start)) { + iov[1].iov_len = ip_frag_size; + hdr.ip.tot_len = htons(iov[1].iov_len); + /* set MF */ + hdr.ip.frag_off = htons( (unsigned short) + (((char*)iov[1].iov_base - (char*)buf + + sizeof(hdr.udp)) / 8) | 0x2000); + ret=sendmsg(rsock, &snd_msg, 0); + if (unlikely(ret < 0)) + goto end; + iov[1].iov_base = (char*)iov[1].iov_base + iov[1].iov_len; + } + /* last fragment */ + iov[1].iov_len = buf + len - (char*)iov[1].iov_base; + hdr.ip.tot_len = htons(iov[1].iov_len); + /* don't set MF (last fragment) */ + hdr.ip.frag_off = htons( (unsigned short) + (((char*)iov[1].iov_base - (char*)buf + + sizeof(hdr.udp)) / 8) ); + ret=sendmsg(rsock, &snd_msg, 0); + if (unlikely(ret < 0)) + goto end; + } +end: + return ret; +} + + + #endif /* USE_RAW_SOCKS */ diff --git a/raw_sock.h b/raw_sock.h index b0e5653..6be0aba 100644 --- a/raw_sock.h +++ b/raw_sock.h @@ -46,7 +46,11 @@ int recvpkt4(int sock, char* buf, int len, union sockaddr_union* from, union sockaddr_union* to); int raw_udp4_recv(int rsock, char** buf, int len, union sockaddr_union* from, union sockaddr_union* to, struct raw_filter* rf); -int raw_udp4_send(int rsock, char* buf, int len, union sockaddr_union* from, +int raw_udp4_send(int rsock, char* buf, unsigned int len, + union sockaddr_union* from, union sockaddr_union* to); +int raw_iphdr_udp4_send(int rsock, char* buf, unsigned int len, + union sockaddr_union* from, + union sockaddr_union* to, unsigned short mtu);
#endif /* _raw_sock_h */
-
Andrei Pelinescu-Onciul