Multipath support for linux kernel protocol.
This commit is contained in:
Ondrej Zajicek
parent
57c574d82a
commit
32b4972834
1 changed files with 157 additions and 21 deletions
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@ -238,37 +238,143 @@ nl_parse_attrs(struct rtattr *a, struct rtattr **k, int ksize)
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return 1;
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}
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static void
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nl_add_attr_u32(struct nlmsghdr *h, unsigned maxsize, int code, u32 data)
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void
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nl_add_attr(struct nlmsghdr *h, unsigned bufsize, unsigned code,
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void *data, unsigned dlen)
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{
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unsigned len = RTA_LENGTH(4);
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unsigned len = RTA_LENGTH(dlen);
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unsigned pos = NLMSG_ALIGN(h->nlmsg_len);
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struct rtattr *a;
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if (NLMSG_ALIGN(h->nlmsg_len) + len > maxsize)
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bug("nl_add_attr32: packet buffer overflow");
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a = (struct rtattr *)((char *)h + NLMSG_ALIGN(h->nlmsg_len));
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if (pos + len > bufsize)
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bug("nl_add_attr: packet buffer overflow");
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a = (struct rtattr *)((char *)h + pos);
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a->rta_type = code;
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a->rta_len = len;
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memcpy(RTA_DATA(a), &data, 4);
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h->nlmsg_len = NLMSG_ALIGN(h->nlmsg_len) + len;
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h->nlmsg_len = pos + len;
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memcpy(RTA_DATA(a), data, dlen);
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}
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static void
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nl_add_attr_ipa(struct nlmsghdr *h, unsigned maxsize, int code, ip_addr ipa)
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static inline void
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nl_add_attr_u32(struct nlmsghdr *h, unsigned bufsize, int code, u32 data)
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{
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unsigned len = RTA_LENGTH(sizeof(ipa));
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struct rtattr *a;
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nl_add_attr(h, bufsize, code, &data, 4);
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}
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if (NLMSG_ALIGN(h->nlmsg_len) + len > maxsize)
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bug("nl_add_attr_ipa: packet buffer overflow");
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a = (struct rtattr *)((char *)h + NLMSG_ALIGN(h->nlmsg_len));
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a->rta_type = code;
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a->rta_len = len;
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static inline void
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nl_add_attr_ipa(struct nlmsghdr *h, unsigned bufsize, int code, ip_addr ipa)
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{
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ipa_hton(ipa);
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memcpy(RTA_DATA(a), &ipa, sizeof(ipa));
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h->nlmsg_len = NLMSG_ALIGN(h->nlmsg_len) + len;
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nl_add_attr(h, bufsize, code, &ipa, sizeof(ipa));
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}
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#define RTNH_SIZE (sizeof(struct rtnexthop) + sizeof(struct rtattr) + sizeof(ip_addr))
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static inline void
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add_mpnexthop(char *buf, ip_addr ipa, unsigned iface, unsigned char weight)
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{
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struct rtnexthop *nh = (void *) buf;
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struct rtattr *rt = (void *) (buf + sizeof(*nh));
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nh->rtnh_len = RTNH_SIZE;
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nh->rtnh_flags = 0;
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nh->rtnh_hops = weight;
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nh->rtnh_ifindex = iface;
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rt->rta_len = sizeof(*rt) + sizeof(ipa);
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rt->rta_type = RTA_GATEWAY;
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ipa_hton(ipa);
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memcpy(buf + sizeof(*nh) + sizeof(*rt), &ipa, sizeof(ipa));
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}
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static void
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nl_add_multipath(struct nlmsghdr *h, unsigned bufsize, struct mpnh *nh)
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{
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unsigned len = sizeof(struct rtattr);
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unsigned pos = NLMSG_ALIGN(h->nlmsg_len);
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char *buf = (char *)h + pos;
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struct rtattr *rt = (void *) buf;
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buf += len;
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for (; nh; nh = nh->next)
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{
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len += RTNH_SIZE;
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if (pos + len > bufsize)
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bug("nl_add_multipath: packet buffer overflow");
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add_mpnexthop(buf, nh->gw, nh->iface->index, nh->weight);
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buf += RTNH_SIZE;
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}
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rt->rta_type = RTA_MULTIPATH;
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rt->rta_len = len;
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h->nlmsg_len = pos + len;
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}
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static struct mpnh *
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nl_parse_multipath(struct krt_proto *p, struct rtattr *ra)
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{
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/* Temporary buffer for multicast nexthops */
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static struct mpnh *nh_buffer;
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static int nh_buf_size; /* in number of structures */
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static int nh_buf_used;
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struct rtattr *a[RTA_CACHEINFO+1];
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struct rtnexthop *nh = RTA_DATA(ra);
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struct mpnh *rv, *first, **last;
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int len = RTA_PAYLOAD(ra);
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first = NULL;
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last = &first;
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nh_buf_used = 0;
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while (len)
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{
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/* Use RTNH_OK(nh,len) ?? */
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if ((len < sizeof(*nh)) || (len < nh->rtnh_len))
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return NULL;
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if (nh_buf_used == nh_buf_size)
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{
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nh_buf_size = nh_buf_size ? (nh_buf_size * 2) : 4;
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nh_buffer = xrealloc(nh_buffer, nh_buf_size * sizeof(struct mpnh));
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}
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*last = rv = nh_buffer + nh_buf_used++;
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rv->next = NULL;
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last = &(rv->next);
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rv->weight = nh->rtnh_hops;
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rv->iface = if_find_by_index(nh->rtnh_ifindex);
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if (!rv->iface)
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return NULL;
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/* Nonexistent RTNH_PAYLOAD ?? */
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nl_attr_len = nh->rtnh_len - RTNH_LENGTH(0);
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nl_parse_attrs(RTNH_DATA(nh), a, sizeof(a));
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if (a[RTA_GATEWAY])
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{
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if (RTA_PAYLOAD(a[RTA_GATEWAY]) != sizeof(ip_addr))
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return NULL;
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memcpy(&rv->gw, RTA_DATA(a[RTA_GATEWAY]), sizeof(ip_addr));
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ipa_ntoh(rv->gw);
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neighbor *ng = neigh_find2(&p->p, &rv->gw, rv->iface,
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(nh->rtnh_flags & RTNH_F_ONLINK) ? NEF_ONLINK : 0);
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if (!ng || (ng->scope == SCOPE_HOST))
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return NULL;
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}
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else
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return NULL;
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len -= NLMSG_ALIGN(nh->rtnh_len);
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nh = RTNH_NEXT(nh);
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}
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return first;
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}
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/*
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* Scanning of interfaces
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*/
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@ -490,6 +596,7 @@ krt_capable(rte *e)
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case RTD_BLACKHOLE:
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case RTD_UNREACHABLE:
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case RTD_PROHIBIT:
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case RTD_MULTIPATH:
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break;
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default:
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return 0;
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@ -497,6 +604,15 @@ krt_capable(rte *e)
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return 1;
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}
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static inline int
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nh_bufsize(struct mpnh *nh)
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{
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int rv = 0;
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for (; nh != NULL; nh = nh->next)
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rv += RTNH_SIZE;
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return rv;
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}
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static void
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nl_send_route(struct krt_proto *p, rte *e, int new)
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{
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@ -505,7 +621,7 @@ nl_send_route(struct krt_proto *p, rte *e, int new)
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struct {
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struct nlmsghdr h;
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struct rtmsg r;
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char buf[128];
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char buf[64 + nh_bufsize(a->nexthops)];
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} r;
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DBG("nl_send_route(%I/%d,new=%d)\n", net->n.prefix, net->n.pxlen, new);
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@ -549,6 +665,10 @@ nl_send_route(struct krt_proto *p, rte *e, int new)
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case RTD_PROHIBIT:
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r.r.rtm_type = RTN_PROHIBIT;
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break;
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case RTD_MULTIPATH:
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r.r.rtm_type = RTN_UNICAST;
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nl_add_multipath(&r.h, sizeof(r), a->nexthops);
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break;
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default:
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bug("krt_capable inconsistent with nl_send_route");
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}
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@ -566,6 +686,7 @@ krt_set_notify(struct krt_proto *p, net *n UNUSED, rte *new, rte *old)
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nl_send_route(p, new, 1);
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}
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#define SKIP(ARG...) do { DBG("KRT: Ignoring route - " ARG); return; } while(0)
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static void
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@ -671,6 +792,21 @@ nl_parse_route(struct nlmsghdr *h, int scan)
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switch (i->rtm_type)
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{
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case RTN_UNICAST:
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if (a[RTA_MULTIPATH])
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{
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ra.dest = RTD_MULTIPATH;
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ra.nexthops = nl_parse_multipath(p, a[RTA_MULTIPATH]);
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if (!ra.nexthops)
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{
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log(L_ERR "KRT: Received strange multipath route %I/%d",
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net->n.prefix, net->n.pxlen);
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return;
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}
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break;
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}
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ra.iface = if_find_by_index(oif);
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if (!ra.iface)
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{
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